Yeah, marketing. Also, I had the same point / question: what do you really get out of this aside from possibly confounding local network attackers if you’re e.g. out at a coffee shop? This seems like a really bad idea if you’re doing something that would get you a DMCA strike, as now their automated systems can just email legal@vps-provider and get them to give up your billing info to sue you.
Censorship circumvention? Not everyone on this planet lives in your particular country. I also trust third-party VPNs and VPS providers (however dodgy they may be) a lot more than I trust my own ISP. That fact alone will tell you all you need to know.
What other utility do these VPNs that are hosted somewhere (like a random fly.io machine) offer? I have a VPN server running in my living room to access my home network when I'm out and about, but I don't see why you'd set one up just randomly somewhere unless you weren't interesting in the masking aspect.