I like the hyper focus on a niche. You'll get negative feedback here from some as it's subscription, but the alternative is a $50 one time purchase that people will dislike too.
One note, I am on 14.5. I just downloaded, then had a screen asking me to give permission my Developer Library folder. I granded/added access, and the app crashed on me. It seems to persistently crash when I try to re-open now as well.