Tanktwo claims several benefits to its string battery system. One is that you only pay for the amount of battery you need. If you're not going to drive more than 30 miles a day, you only put in as many cells as you need, saving money and weight. Need to take a longer trip? Just fill up your tank at a service station (which can charge the cells at off-peak hours for redistribution), and get a credit for returning the cells you don't need anymore when you're done with them. Swapping a full tank of cells takes about three minutes.
There's also no need to worry about degradation or your battery chemistry becoming obsolete. If battery cells improve, you could end up with more maximum capacity than when you bought your car just by swapping out for new cells, theoretically helping the car maintain more resale value over time.
The battery performance doesn't suffer if only some of the cells are degraded, as happens in traditional batteries. That chip in each cell allows the system to route the most efficient circuits out of the many possibilities, stringing strong cells and weak cells into their own groups using algorithms inspired by internet and cellular protocols. Twotank would allow the pickiest drivers to select the higher quality units for a higher price at service stations, though, similar to choosing higher octane fuel.
Perhaps the biggest obstacle with the Tanktwo string battery system is that it's unfamiliar. Compared to what we're used to, it seems weird (to the point that one double checks to make sure this isn't an April Fools' joke), and changing the way people think is difficult. Of course, there's the infrastructure thing, too, but many of the supposed benefits are available even if you rarely swap the cells. Despite its promises for cheaper, better, and more convenient batteries, Tanktwo's system is something that would require a lot of convincing and explaining before it could ever take off, especially after the original hype of swappable batteries has come and gone. Tanktwo is currently pitching and testing its battery tech, so we'll see if that groundwork eventually pays off.