Some thoughts:
The price point is impressive if you can sell at only ~$50 more than a standard lead-acid battery. If pressed to find a flaw, I think the biggest is one you've already identified:
There’s one: you can’t run your lights and/or stereo as
long with your engine turned off. Ohm’s battery reserve
comes in at 10 amp hours; most lead-acid car batteries
come in at about 45 amp hours. If you can run your
stereo with your engine off for three hours on your
current battery, you’d be able to run it on Ohm for less
than an hour.
Nobody with a modern car or SUV is going to get three hours' runtime for their accessory equipment. With the original equipment (AGM lead acid, 70 AH/450 CCA) battery in my two-seat passenger car, I'm lucky to get 15 minutes' worth of stereo/nav/etc. operation with the ignition off. There's no conceivable way that 10 AH is enough for this application. The more "luxurious" the car, and the newer it is, the worse this problem will be. Meanwhile, LiFePO4 battery cost will probably go in the opposite direction, leaving room for competitors to offer more power for less money.
So I'd reconsider the size of the LiFePO4 battery, even if it makes the product cost a bit more. You need those high-end buyers. You're not going to sell these to Joe Sixpack for installation in his '98 F-150 pickup.
And yes, your marketing materials are grossly exaggerating both the environmental problems with lead-acid batteries and their typical service life. There is clearly a global regulatory jihad against lead in all of its forms and uses, though, so you do have that going for you.
Edit: Don't forget that auto stop/start is growing in popularity as well. I think it's actually mandatory in some (European?) markets. OEMs are moving toward "smarter" (read: DRM-locked) batteries to handle these additional requirements. I wonder if a better business model might be to offer recycling/rebuilding services that swap out lead plates for LiFePO4/supercap hardware in existing batteries?