If you look at everything from an investment & return angle only,,it's not going to be worth the investment.
But the idea of just plain enjoying an older firearm and maybe also the enjoyment of bringing one back from the edge is sometimes over looked.
It is a hobby after all to most people. The money could be spent on many different ventures and hobbys that'll never bring you any plus monetary return either but instead bring enjoyment.
That's what it's supposed to be about.
I have a Meriden Single Bbl hammerless damascus that I'm restoring (slowly). It'll never be worth anything much, but it's a neat, seldom seen gun and I like it. So what's wrong with those reasons.