On the other hand it could fish up your Province from the bottom of your deck.
Why in the world would you want to do that?
Looks like you didn't read DrHades post to which jotheonah was responding. In a word: Tournament.
Ahh. Actually I did but the context of reading that and not seeing a quote or "@DrHades" etc. made me think it was him coming up with a way to use Pearl Diver and announcing it. In that case, I fully agree. I've done it myself. However, you need to have the Tournament in your hand and must remember to play Pearl Diver before the Tournament to see if you can get a province.
This is actually not true. You need a PD, a Tournament and another cantrip to make PD usefull like this. Imagine this situation:
I have PD, Tournament, C, C, C.
a) I play PD first, drawing Estate and the bottom card is Province. I don't want the Province on the top NOW, I will draw it without my Tournament!
b) I play Tournament first, drawing Province.
I think this is PD's deadly weakness - if you FIRST put the card and THEN get the +card, it would be a good card to play. I did not playtested this version, so I don't want to say that Donald X. should've made it this way, but the PD as it is is IMO one of the most useless cards ever made and I read it as "+1 card, +1 action" completely ignoring the ability...