Upgrade or alternative upgrade?

Firstly, yes, on the second week, we build Draconians and sacrifice Tanos, but on the first week, we build a Warehouse and immediately gain +1 crystal per day. On the third week, we immediately rush and clear the mine with Draconians; firstly, there are usually crystals nearby, and we also eliminate the neutral creatures guarding other crystals. As a result, we have an increase of +2 crystals, which is 14 crystals by the end of the week, plus what we accumulated from the 2 previous weeks. In total, we can easily build Tanos. What's unclear?