[Wicher]

Wear on the chain is greatly increased though on a 1x12 versus a 2x10, because of alignment.

Tolerances on a 1x setup are also much tighter, not ideal for long distance cycletrekking adventures.

Also, with a front derailer, dropping the chain to a smaller cog in the front to get to a lighter gear results in much happier shifting than having to lift the chain to a larger cog on the rear derailer when going uphill.

When MTB racing you can really get some advantage out of shifting combination discipline using a front derailer, when going from a downhill into an uphill.

I'm sad it's hard to find a 2x setup on new bicycles nowadays :-/