Not sure if this has been posted before, but Watchtower might actually make Populate quite interesting in Tomb games if there's enough useless Kingdom cards to be trashed right away. You could also put cards you actually use on top of your deck immediately, including Watchtowers, potentially enabling this multiple turns in a row, assuming you're able to hit $10
I mean, if you're hitting $10, then provinces are usually going to be the best way to go pretty much every time, but in situations where you're only using 3 of the Kingdom cards, getting 7 VP every time you spend ten without further piling out the province pile might be the better route to go, especially if you're down to 2 provinces left and are behind and don't want to risk getting the penultimate province.
This seems very situation specific and probably isn't all that useful most of the time but it strikes me a sort of combo that could come in very useful in the right situation.
Perhaps Big Money + Watchtower where you trash *everything* upon buying Populate would work the best?
I haven't tested this out in live play before, it just came to me as something that might work.