Asking users to use developer mode is not easy, and a huge barrier to entry that most would just not bother and download something else from the Play Store instead.
1. User downloads an .apk using a browser
2. User tries to open it
3. Android prompts the user to allow the browser as a trusted source
4. User agrees by flipping a switch
5. Installation resumes
6. User enjoys the app
https://developer.android.com/distribute/marketing-tools/alt...
https://android.gadgethacks.com/how-to/android-101-sideload-...
This is, however, a great thing to have.
A better substitute would be using F-Droid. By the way, some free software apps are not gratis on the Play Store but are on F-Droid.
It can still be confusing to manage two app stores for some people, while installing an app from a downloaded executable is usual on Windows, so Krita probably did the right thing.
>Unlike the Windows and Steam store, we don’t ask for money for Krita in the store, since it’s the only way people can install Krita on those devices, but you can buy a supporter badge from within Krita to support development.
I don't know about the Windows store because I don't use Windows, but doesn't the Steam store allow you to put up free tools? Godot Engine is available for free on Steam, IIRC.