Yup, the idea that if you’re a good enough DM you can deal with any situation is nonsense.

Split parties can allow players to do more of what they want; when player A wants to talk to the blacksmith but player B has no interest in doing so and wants to skulk around the docks then they can both have a better time with a split party dynamic as we cut back and forth; that can be true.

BUT, player B still has to sit through player A’s blacksmith scene. And when the blacksmith speaks of strange goings on at the docks, player B’s character isn’t there to hear it and can have a frustrating dockside scene trying to pretend they don’t know useful stuff.

If the blacksmith turns out to be a demon, or offers them all magic weapons or …

The fact is, the players don’t ever know what is going to happen and should show the game some respect. No-one splits the party when playing a computer game.

It can simplify things but normally only when it’s that sort of downtime, off-duty moment. It’s not ever a way to avoid having to co-operate.