GM packs are well protected and now have sealed charge connector and even heatshrink on the balance lead.
The case is really convenient, plus it has a switch already inbuilt and is portable as you can remove it from your bike to charge inside easily or when temperatures are at extremes.
I don't personally use Ping batteries, but I have heard nothing bad about them. They are not a super high power battery anway.
From what I've seen the pack is protected by tape and possibly cardboard... So I assume you would need to waterproof it and work out a way to mount it (in a bag etc.) and worry about charging leads and connections to your ebike...
Personal choice, but I would go with the 48v12Ah..
Cheers