The downside is that some useful features like background removal will never come to the non-subscription version. OTOH, the subscription is cheap if you think of it as license cost for an Adobe alternative.
I mean, it's sort of inevitable. Eventually, Canva will find itself under pressure to grow revenue (or even just weather a downturn). The maintenance of a complex desktop application is expensive and there will be pressure to increase "conversions" by putting more and more of the useful functions behind a paywall.
That said, their immediate goal is probably to take away customers from Adobe, and right now, the product is free, has more features than the old Affinity, doesn't need to talk to activation servers on an ongoing basis, and doesn't auto-update. So we should enjoy it while it lasts.
This never happened to me when getting something from the AppStore, or from anyone else really. And that’s the problem with cloudgarbage, you have zero control over it.