I would say it's only worth it if you're marrying higher level Pets, for Standard and Exp Poss. Even those are worth far less than before, but if you can invest in decent Pets (Making them from scratch is a bad idea), leveling them, demonic fruits every time they're ready AND you have the patience to wait until they bring you your investments back, let alone bring you some profit and possibly hold on to the Possession(s) and Fairy/ies you get from Marriage for days or weeks until they're sold - Then sure, you can make it work.
Not trying to make it sound tedious, but it's an investment that takes a fair bit of starting money and A LOT of patience until it brings you decent profit.
