If you remove your yuri goggles, this is only a BFF relationship in construction.
This reminds me of an earlier post in this thread which still perfectly describes this manga
These girls better be careful. If they engage in so much platonic friendship, they might end up in a friendship triangle. Then the only solution would be to confess their friendship to each other.
That would eventually lead to them putting on friendship rings and friendship dresses and holding a friendship ceremony. After that they'd have a platonic sleepover at a vacation resort and friendship each other's brains out.
Then they'd go back home, move in together, adopt a child, and spend the rest of their lives with each other.
You know, as friends.
Hell, these days friends are even bump-bump-bumping each other in the halls. In broad daylight, in front of everybody.
And this buying each other ice cream and drinks from the vending machines: compensated friendship.