Why use "payments" in the phrase "global payments system"?

I looked up the dictionary, the word "payment" is only countable in the meaning of "a sum of money paid or expected to be paid". However, I think in the phrase "global payments system", the meaning is more close to "the act of paying sb/sth or of being paid", in which "payment" should be an uncountable word, so why do we need to add an "s" after "payment".

Can I say "global payment system"?

Solution 1:

Lexico describes "payment" to be a mass noun when used to refer to the act of paying. However the sentence

I made two payments to my credit card account

clearly uses the word "payment" as a countable noun, and the most natural way to understand the word is to regard it as referring to the act of paying something.

A global payments system is a global system for managing such acts, so the countable noun is correct. It would also be correct to refer to such a system as a global payment system. Google ngram shows that the latter is more common, especially in US English.

Solution 2:

"Global payment system" and "global payments system" takes the form of NP1 + NP2, and thus convey the meaning of "NP2 that is associated (in some way) with NP1."

Payment (uncountable) = the general action of the verb to pay. "Payment was made on Sunday."

Payment (countable) = one instance of the action of the verb to pay. "He made three payments and then stopped."

Thus "Global payment system", gives "the system that is associated with global payment" and as payment is uncountable, this gives us "the system that is associated with (i) the concept of, or (ii) the homogeneous category of, global payment."

And "global payments system", gives "the system that is associated with global payments" (countable use) -> "the system that is associated with payments that are global/made globally."

At a practical level, I believe that few people can be bothered to make the effort to see the difference, and so the phrases are broadly interchangeable.