Why one coaching account covers it all.
You will not need multiple subscriptions/accounts to coach across a variety of disciplines. If you coach more than one discipline, you can still do all your coaching within the same subscription/account. All that matters is that your package covers the number of clients you need it to.
Tip: You can only choose one discipline when setting up your profile but the discipline you choose won't affect your use of the app in any way and your clients don't see your choice.