I thought it might be a good idea to add a little description in the desecration panel which tells you what will happen.
Ie, when you click the desecrate button it says
Desecrating Binlor will remove all your resistances, grant X piety and make your god more forgiving of mistakes. Are you sure you want to destroy this altar? Yes/No
That would make it very clear and make sure no new players are confused as to what desecration does.
This way also doesn't require referral to a codex or the wiki
edit: For instance i just forgot that desecrating mystera increases BOTH resistances, not just magic. Almost cost me the run