I don’t really draw so I haven’t used it as much as I wanted to but that was one purchase that I never regretted. Also helps that it’s not subscription type. To this day anytime someone gets an iPad, I make them try the app.
And given that it was a non-pricy one-time purchase, and not a subscription, why would they regret it? The cost per hour of usage is only going to keep decreasing over time for them, as long as they keep using it in some capacity occasionally.
I don’t regret it because I can see that what I paid for is worth the value of the app despite not using it as much.