Are Slabbed Key Coins A Wise Idea?

In trying to complete 2 sets, I've found that there are many times where a slabbed example is the same or less cost-wise then a raw coin. I was looking for a nice 1932-P Washington quarter, and it seemed like 99% of then (raw or slabbed) were priced as if they were '32-D or 32-S's (Close to or over $100). I found a nice slabbed AU58 for $15.99, so I bought it. I later found a raw '32-P elsewhere (ie, not ebay) for $17.50 that I would grade at MS-61 or so.

I'm also finding the same with Franklins. Looking for a 52-S and 53-S, and the prices for raw are as expensive (overpriced) as slabbed. I may end up with slabbed for both of them.

Both of these sets are Dansco albums, so if I get slabbed, I'll end up inserting a photo of the coin in the slot. Not ideal, but still works.