Well for me, it's not so much trying to take Kubo to task for the "Main Character Dynamic Entrance when All Hope is Lost" trope that exists in every Shonen manga...ever? Yeah, definitely ever. It's just that it's usually handled a little better in other stories. In DBZ, holding out for Goku means that Vegeta willingly throws himself into an ass-whooping 50 times; Piccolo gives an epic speech; the Z-rabble will put forth the effort. There's struggle, fight, exchanging of techniques, desperation power levels, etc. It keeps things exciting.
Speaking of "not being enjoyable since it would be meaningless by the next chapter" . Its true, we all know these fights are in the end to entertain us til the main event. but dont say it as if its something only Kubo does :P Its like Konoha defending against Pain, til Naruto comes. Or how the Z fighters try their best til Goku comes. Its not that exaggerated in One Piece, but it happens sometimes too. Pretty much every manga / anime does this. But it still enjoyable for me.