What is the purpose of appflow?

Hello guys!
I would like to understand the real purpose of appflow.

If I can use bitbucket there, if I need to have an apple developer account for build ios and optionally a google developer account.

Why still pay for a monthly appflow plan? I still do not understand what benefits I have! I think it’s cool live update, but google and apple also update the device …

I requested my company to hire but I am not finding arguments to defend the renewal … Can you help me?