Right, this is not news at least pricing isn't. Who knows what $20 would net you with PS+ or XBL so for me the online pay alone is worth it. Not to mention...this service almost does everything PS+ normal subs so. A 3mo sub is 25 bucks and you get online, cloud storage of 1GB, and discounts...all of which is being offered with Switch Online. In addition to the NES games.

Free would e better...but nobody else is making online gaming free, Nintendo was doing this for years out of their own pockets. Even if you don't play online, the 20 NES games alone would cost you $100...without online play. For a third of the price as the competition I think this is VERY fair and those who still want it to be free are, to be frank...very cheap.

By being on a different system..? That was exactly my question. Is it really not limited to a specific system?

Nintendo hires people to play the game when there is not enough people to fill a lobby in a given area?
That is what it would take to ensure a game like ARMS can reliably be played online.

ARMS didn't sell that well.
https://www.nintendo.co.jp/ir/en/finance/software/index.html
https://www.nintendo.com/switch/online-service/
Now that pool of available players is going to be reduced considerably.
Anecdotally: many people bought the game, and either didn't play it much, or have stopped playing it.

Given the entire ARMS player-base aren't in one region.
It is unlikely  that there will be enough people in countries like Australia, to reliably fill a room.
ARMS matches will either be very hard to find, and/or between people who aren't in the same region.
A large distance between players, leads to high ping, which leads to a worse overall user experience.
(Assuming you can find a match)

Games from GBA would also be good :)

Misuse it to clone pokemon? people did that? It's probably was a joke ?

In Splatoon 2 and Arms. Australian players play with a lot of Japanese players, so I think Nintendo decides to combine those 2. 

And have you played Arms? Because in my reply to you I meant it by the game will put people in a room that has a capacity of 8+ players. If a room have only 3 people, the game will start placing people who just booted up the game and go online into that room.

I have played ARMS, in Australia.

Japan and Australia are pretty far away.
A packet traveling between the two countries will have generally have a longer travel time, than a packet traveling domestically.
Due to distance, processing, ect.
Meaning a player will generally have a worse user experience, if they are playing with someone outside of their country.

Nintendo probably just compares the player's ping to various servers, rather than locking players into set regions.