Why switch to a air lock?

Why do we switch to an air lock a few days into fermentation? Why not just keep the blow off tube run into a bowl of sanitizer for the duration?

You can use for the duration of the ferment. When I use carboys I always use a blowoff and leave it.

You don’t need to switch. I keep the blowoff on til fermentation is done.

Only reason to switch would be to save space.

I never switch. Blowoff throughout.

I haven’t used a blowoff tube in years, and I actually don’t even use an airlock half the time anymore…just a piece of foil covering the top of the carboy works just fine.
When I do a secondary stage, I’ll always use an airlock there.

Or if you have one tube and multiple beers.

I guess I need another tube.