I certainly lost interest in the 3DS as soon as I heard about its 3D Focus. I bought it despite (!) 3D after KH3D came out and after some tryouts I always play without 3D. For me it is as useless as the stylus controls because both do not offer anything valuable for my personal gaming tastes (well, the stylus controls work with games like Phoenix Wright and Professor Layton... but it ruined "normal" games for me. I had a hard time with TWEWY for example.)
By the that logic, HD is as useless.
And you can use your fingers instead of stylus. That what I do in most DS & 3DS games that use touch screen controls.
You do know that you can adjust the volume of 3D right?
A lot of people seem to forget that the 3DS does more then 3D ON & OFF, you can adjust the 3D volume at 10% & 90% & 20% & 80% & 70% & 30% & 40% & 60% & 50% & etc.
I guess its safe to say you never used the Surround Sound audio of 3DS games like Kingdom Hearts 3D, since you never try 3D visual, it's safe to say you never use Surround Sound (3D Audio) in any & all games.