I did this with Bitcoin before (a long time ago), just for the heck of it and never made a profit - maybe lost a bit. Saw similar ads for ETH mining contracts and did the math and I drew the same conclusion as you. The only way this might be worth it if you wanted to get some more anonymous "fresh" coins. But you'd have to be really careful about how you pay for the mining contract. If you can do that then you probably know how to get anonymous coins anyway.

Oh yeah, and for some coins like ETH never underestimate the potential of them switching to PoS and killing mining overnight. I actually wish they would! Lets focus on owning and using ETH not mining it and wasting energy.

The only time it seems to be worth mining is very early on before others are mining and you can quickly get ahead of the game. I've done this before with some early alt-coins. Made a few hundred $ - enough to pay for my graphics card. Oh, and if you can get the hardware and electricity for free - that'll help! Get your cards cheap on eBay during a crypto-slump and then run them at work with someone else paying ;-)