If you are not interested in subscribing to the new Apple Creator Studio bundle introduced today, you will officially start to miss out on some new features. Apple said some "exciting new intelligent features and premium content" in Pixelmator Pro, Keynote, Numbers, Pages, and Freeform will only be accessible with a Creator Studio subscription. In the U.S., a subscription costs $12.99 per month, or $129 per year, while college students can pay a lower $2.99 per month or $29 per year.
As long as you’re still able to use the one-time purchase with the features present at time of purchase (and one would hope a reasonable duration of security updates) then what’s the problem?