That is a DOT tank (way more puncture resistant than a plastic gas tank), not one for your BBQ. Just because you don't understand something doesn't mean it isn't effective. That 5lb tank lasts for months and can be filled anywhere. Meth is expensive, very volatile, consumed rapidly based on weight, and often stored in a substandard containers - and E85 is a regional delicacy and unobtainable for many folks.
Propane shares a stoichiometric measurement very close to gasoline and is easy to tune for that reason... especially if you live on the gas scale and choose not to use Lambda.
I could just keep going on about the benefits but if it doesn't come ready-to-go from a known vendor it won't catch on in this community.