What's the advantage of using a hardcase Lipo as opposed to a soft cas in a jammin sc10?

well, there isn't an advantage performance wise with a hard case its just for protecting the cells inside the battery.

Maybe a little weight...but you want to use hard case to protect the cells

Not familar with the RC, but with soft case you need a way to adequatel secure it - I usually use 3 velcro straps with mine. If thats not poss with your rc, then hard case would have advantage - easier to install and run.

You can't allow soft cased lipos to move, thats when trouble starts.

The hard case also distributes the pressure from the straps or whatever. Sometimes the localized pressure from the straps causes problems with soft cells, compounded by impacts.

But primarily to protect from crash and intrusion damage, especially from other cars, obstacles you might hit, etc.

Soft packs are commonly used in airplanes and helicopters which do not subject the pack to the many bumps and jolts a car gives, except in crashes.

Many tracks require hard cases as a safety precaution so they don't get punctured but the case doesn't do anything to prevent overcharging and other abuse. ROAR requires hard cases at their sanctioned races.

Most tracks that I race at allow soft packs as long as they're properly handled and secured in the vehicle. I use soft 5S packs in my 1/8 buggy strapped in with four velcro straps with no issues.

'Soft' cased lipos are not really that soft at least as far as the ones I'm using - Turnigys, Neuenergys, Hyperions and Flightpower lipos - 2S, 3S and 4S lipos - these have never shown even a hint of a strap impression.

Soft is somewhat of a misnomer, at least as far as the ones I've used. Yes, they don't have a truly hard outer skin, like plastic or composition, but 'soft' may be a poor description at least with the lipos I have used.