Sounds akin to the cheapo flashlight batteries that die after a very short period of use.
Many people will buy into this Tesla deal simply because they will NOT do the math and simply "feel good" because they have a BACK UP system.
Has similarities to it much like Obamacare. Sounds good on paper. Just don't try to use it to SAVE money.
Having a backup system is a good idea. Why do we buy ammo/guns, store food, buy insurance, buy gold/silver. Its a backup and knowing whats happening with the economy, we need a back up system for electricity as well