Should I take the Wisdom skill?

...and also, wherever there are computers, they like to build all sorts of useless things in their castles.

A fully built Guildhall is sometimes the last thing a computer sees before it dies. Sometimes you take a skill with the goal of getting a specific spell (level 2 or higher), and if it's not in that Guildhall, the skill loses its meaning. In general, buying at least one hero with that skill (on the map) never hurts. But many powerful spells will be of little use without upgrading a particular school of magic – this should also be taken into account. And it's not always necessary to max out Wisdom to Expert level.
Maybe it's not entirely on topic, but I want to add to the discussion with this question (I didn't notice it in "Secondary Skills in Heroes 3" and other topics). If, when a hero levels up, they are offered to either increase an existing useful skill or take a new useful skill – what is the best course of action?

...a hero with a good level 3 spell (restoration, meteor shower)...

actually, these are level 4 spells; you need Advanced Wisdom and Expert Literacy.