The group special is once only, however, if you look at the reward rubric, you will see the REGULAR reward, the reward that you gain for every attempt, increases with number of group mate in team.

This SA is a lot harder than the previous ones, mainly because Minato cheats and ignores priority for some reason (Like the Kages in Sealed Ninja teams) It's about how strong you are for your level that'll help or hinder effective completion of Strong Approach.

It's true though you get more group coins completing all regular runs as a Team of 3 with members from your group, they need to be clearer about it, why even have the bonus group run at all if running with a group is the most rewarding way anyway for normal runs, it just adds to confusion. They could have presented that information a lot better.

It's not up to Oasis to balance it, as it was developed by Tencent in China for the original version of the game, what Oasis can "possibly" do is decide which SA we get since it's currently on a 2 week rotation and maybe just not activate the Minato Strong Approach.

I find SA to just be tedious considering how easy it is to level BA Cloth to Level 27 for no cost and how hard it is to get your BA Rank up even if you buy the threads.

So it means a portion of what I get is entirely useless and has been for months, and the rewards are no better or worse from SA to SA, so it leaves you wondering what the point is when the SA last week may have been the simplest thing in the world to finish but this week it's a frustrating Nightmare, and on top of that the rewards are also no different/better.

Even more so now knowing that the best reward is with a team of 3 group members, Strong Approach ranking is almost entirely irrelevant, why would you ever go for a SA score when it's not even beneficial?

Poor game design all around.

Here is some visual aid:

https://imgur.com/UHPzjps

The stuff in yellow is what you are talking about

The stuff in red is what I'm talking about.

For the EXTRA group run, on top of the stuff in red, you receive extra reward, the stuff in yellow.

But for EVERY run, you receive the reward in red. And as it is, the more group member you have in team, the more the reward for this red part.

What PraiseLuka said is useful while yours is only to incite drama. There's a difference.