This is a pretty good guide but I CTRL+F for the word 'trust' and come up empty.
The most important factor in approval of witnesses is trust that they will act in the interests of the blockchain. Therefore you trust that they act in the interests of making your own stake, which you're voting with, more valuable.
Trust is certainly an essential factor in voting for a witness.
Do you have an opinion as to whether the current bid-bot craze is increasing the value of our stake?
Personally, I do not, but I'm interested to learn from long-standing witnesses, particularly those without obvious connections to a bid-bot, how they see the situation.
Thanks.