Why Sealed Tuners?

I'm Kind of curious why some makers use sealed tuners? And others open geared?

My 7 mos old Ko'Aloha KTM-00 came with a sealed tuner that was loose and got looser as I used it. It didn't hold the string in tune very well. Ko'Aloha sent me a replacement.

You can't tighten or adjust anything on a sealed tuner (Only exception are the "sealed" tuners on my Fender NoHea. There is an oil hole on those.)

So why use them? Is it strictly aesthetics?

What's your preference?

I think part of the reason is appearance. Sealed tuners look neater. Theoretically, having them sealed should prevent dirt from getting inside, but I doubt that's the case. Open tuners will let any dirt and dust fall out or be cleaned easily. I'd like to see someone disassemble some old sealed tuners and see how clean they are inside. Dust, dirt, and moisture get everywhere. Still, given the option, I take sealed tuners.

https://www.cigarboxguitar.com/knowledge-base/how-to-use-sealed-gear-tuners/
https://www.jazzguitar.be/forum/guitar-amps-gizmos/17344-your-opinion-advantages-sealed-tuners.html

I cynically think it's to hide the poor quality of the tuner mechanism.

Keeps the mojo in

But then again planetary tuners (Gotoh UTP’s and Pegheads) must be considered sealed tuners also. I wouldn’t say that they are hiding inferior mechanisms.

Sealed tuners keep the rain out in Summer and the snow & ice out in the Winter. Open tuners are fine in the Spring and Fall.