At least for me, that's the charm of Futaribeya. They know they're in love with each other, everyone around them knows they're in love with each other, and even the readers too.
It's comfy as fuck, it's fun to read, no drama bullshit, and no excessive kissing and (god forbid) fucking on every chapters. Those cliche made me bored real fast.
And if I wanted to watch 2 girls fucking each others' brains out, I would rather read hentai doujins, not 4komas lol.
TL;DR Futaribeya is nice because it's comfy af.