lost_cause Creating and maintaining Google burner accounts would be an extra annoyance for his clients.
I have personally not found that to be difficult, at all. After creating a Google account with Play Store, no additional work is required to maintain the account. Signing up is also easy. I've written about creating a Google account without providing personal info here: https://listed.to/p/vznkmwrV5w
The fact that an account is needed just to install apps is annoying, though, I agree with that.
As to why this author recommends specific app stores, I think that is up to them to decide if they would like to elaborate on that.