Build a native iOS app via storefront api, admin api, and ajax api

Hi guys,
I want to build a native iOS based on Shopify API, and I found that I need to use both storefront API, admin API, and ajax API. Is it common?
For example, I use admin API to get one customer’s orders, use storefront API to let the customers log in, use ajax API to operate the cart.

I am a little confused. Is it a common pattern? Why is there no API that can provide these functions

Thanks!

hey, the storefront api should be sufficient to handle this for you!