[Discussion]

Define the principle of truthfulness. Fair play, whether for money or not, does not violate any principles of truthfulness.

Pardon me, but the question in the first post was "Gambling, betting, and so on......good or bad?"
To answer the question, it is necessary to determine from which platform this situation will be analyzed. Based on the question, where categories of "good" and "bad" are specified, it is obvious that one must rely on some ethical traditions or values and choose a starting point—something to push off from.
The most authoritative and ancient ethical traditions that answer the posed question are religious beliefs, in which what is good and what is bad is fixed in the form of commandments or rules. It is another matter if we rely on the tenets of capitalism, a set of views of modern society that justifies all types of activities for profit, up to the exploitation of personal connections, relatives, trading one's own body, etc. From these positions, gambling has a right to justification: "In the conditions of so-called capitalism—it's no worse than everything else," as you said. The main task of capitalism is precisely to justify and involve an increasing number of new participants in the process of extracting profit, without regard for any ethical norms. Here, the question of justice, authenticity, exploitation, etc., arises, but that diverges significantly from our original question. The only thing that can be noted is that a system of views based on capitalism is not authoritative in establishing what is good and bad, because:
1) capitalism itself is relatively young and its tenets have not been fully tested by time (how long have formalized cap. relations existed? 200 years? 400 years? In its modern form, no more than 100 years.)
2) Secondly, the problems and internal imbalances in the development of capitalism clearly testify to the failure of this system, as evidenced by growing economic problems (national debt, illegitimacy of the financial system, etc.), increasing inequality between people, growth of unemployment, etc.
Thus, the platform of capitalism is not authoritative for determining whether it is good or bad to gamble for money, because capitalism will justify anything to maintain its own existence.
Therefore, it is necessary to turn to proven ethical systems, which are now mainly based on religious traditions. Which traditions are these? The most prosperous nations now are the Arabs, Jews, and Indians—all characterized by an orthodox preservation of and commitment to their internal religious principles. This position is highly debatable, so let us not consider it in detail and return to the essence of the question.
What do the main time-tested ethical doctrines say regarding gambling for money?
For example, http://skopych.kiev.ua/2012/08/16/azartnye-igry-opredeleniya-i-osobennosti-chast-1-fil-dzhonson/
Or based on Christian values: "Man is by nature impatient, and he wants to acquire many things without additional effort, instantly, which contradicts the natural flow of life, but is possible under certain circumstances in gambling." http://pokrov.dp.ua/publ/osnovy_pravoslavija/kak_stat_millionerom_za_dve_minuty_prada_ob_azartnykh_igrakh_chast_i/2-1-0-112
Or here, comrade Lazarev has taken up the Indian Vedas and examines the principle of truthfulness right here http://lazarev.org/ru/interesting/full_news/4_principa_istinnoj_religii_i_4_osnovnyh_principa_bezbozhiya/
It can be concluded that any time-tested ethical school places gambling for money outside of its values. Therefore, betting cannot be called a good thing. It is another matter that few people strictly adhere to ethical principles now due to the degradation of society as a whole. This is also a debatable issue and requires a separate topic for conversation.
It was said: The example with the lottery shows nothing new. It only shows what is already known—that there are mentally unstable people.
Quoting: "It is estimated that in the United States alone, there are about 10 million people addicted to gambling. At the same time, the average debt of a gambling addict is about 80 thousand dollars. This problem is scarier than alcoholism. Furthermore, in places where gambling establishments flourish (for example, Las Vegas or Atlantic City), suicide rates are three times higher than in the country as a whole." One can question this quote, but are there other figures testifying to the prosperity of society based on income from gambling? Of course, there is a big difference between playing for a small bet in Heroes and the entire gambling industry. However, these are phenomena of the same kind, and the size of the bet cannot be a justification.
Further productive discussion on whether it is good or bad to gamble for money is difficult, because first, we must reach a common denominator, a starting point from which we can push off. I assume that next there will be questions like: "Be so kind as to provide a link to an authoritative statistical source that takes into account all winnings (not isolated newspaper cases) and the fates of the winners, statistics for a year, five years, 10 years, 20 years..." Which will reduce all efforts to answer the original question to nothing.