Why bother using a product from a company that is notorious for failing to commit to most of their services, when you can run something which produces output that is pretty close (and maybe better) and is free to run and change and train?
Stable Diffusion is the Linux-on-the-desktop of diffusion models IMO
(I agree w/ your comment on trusting Google - pretty sure they'll just phase this off eventually anyway, so I wouldn't bother trying it)
Linux entered the market at a time when paid alternatives were fully established and concentrated, servicing users/companies for years who became used to working with them. No paid txt2img offering comes anywhere close to market dominance for image generation. They don't offer anything that isn't available with free alternatives (they actually offer less) and are highly restrictive in comparison. Anyone who is doing anything beyond disguised DALLE/Imagen clients, has absolutely no incentives to use a paid service.