[hobs]

I assume for the same reason you ground your home, building up charges is a great way for Bad Things to happen.

[posix_me_less]

Why would a phone pouch/box build up great charge? You don't ground your home because of charge buildup either - grounding is there to decrease the chance a thunderbolt will run through precious things, like house walls, people, electric wiring etc.

[hobs]

You absolutely want to ground your home due to charge buildup, I have seen the exploded appliances, no lightning required.

[oasisbob]

Grounding and bonding is done for many safety reasons. Reducing stray voltage is certainly one of them:

https://www.mikeholt.com/technical-stray-voltage-newsletter-...