On the occasions that a LPG truck has a structural failure and blows up, the driver is never buried. There is nothing left to bury. Do you want a smaller version of such a tank inside your car?

LPG is definitely cheaper. Aside from that, there are remarkably few benefits of using it as an alternative to what we use now.
Like all carbon-based fuels, it is not considered environmentally friendly.
-NJ

I would not consider this a really viable alternative since LPG is still a fossil fuel.