This testing is important to Samsung,
because it's necessary to test how much of different scenarios is possible.
Every functions in every situation, every network,
SIM card, resolution, application, settings,
language version,
every version of a certain apps in different situations.
Some feature you even don't know about, might be a crucial to someone else.
But no one is using absolutely everything.
It's literally impossible.
For example,
I can't use Google Wallet,
and I'm using the my smartphone for the contactless payments since maybe Samsung Galaxy S8.