Software as a Service is only a value when the service offers you something that the software on its own cannot do; otherwise it’s just rent seeking.
Paying for cloud storage, for continuous content updates (especially news), or a server to process or generate content that can’t be done on my device, all fine. Paying for a messaging service to pass my messages to others, or for a game to maintain servers for multiplayer play? No problem.
But a subscription to remove ads? Your app doesn’t need an external server to do that. That’s rent-seeking. Same with a subscription to unlock widgets or some third-party connection.
A subscription for regular software updates are right on the line for me. In a sane world, the software package you purchase would be provided with some amount of security updates, but you wouldn’t have to pay any extra until you decided to purchase the next version for new features. You know, like it was until Adobe decided to upend the industry. (Incidentally, it’s weird that Adobe has gone from being the poster child for rent seeking in software to one of the more reasonable companies that’s doing software as a service. I still hate that there’s no way to get their software without a subscription, but at least they are providing some form of continuous value in the form of continuous updates, as well as fonts and stock images and such.)
On the other end of the spectrum you have something like Minecraft, where my ($20? I don’t remember) purchase from over a decade ago is still receiving regular content updates for free, multiple times a year, with no subscription needed. I can pay a subscription fee to get an online realm for myself and my family, but I don’t have to because I can also just set up and operate a server myself. More than reasonable.