It’s specifically for Discourse. I’d be surprised if they ran that advert and didn’t test it out.
No reason why 2GB VPS can’t be had. DO is a bit pricey… like… a bit… but it has a nice looking, easy to use interface, and they paid lots of monies for adverts to be so well known with so little experience compared to some other hosting companies… so that’s how they recoup the losses, they jack up the price.
I could break even at $5/m 2GB, but how would people know I existed?