Consumer Reports touches a bit on that. One advantage is for example that you don't have to worry about the maintenance and reliability of the combustion engine.
I leased a Volt for 3 years to try it out without having to commit to the early adopter risk. Oil changes were every 20,000 miles. Occasionally the engine would turn on and run automatically because I hadn't used it at all in a few weeks just for maintenance sake.
For a gas first approach like most hybrids I think it's a bigger concern. In the Volt since it's just a generator I don't know if the maintenance burden is quite as much of a concern.
GM initially promised that the first generation Volt would be fully series-hybrid--the engine would drive the electrical generator and have no mechanical connection to the rest of the powertrain. This means that the engine can spin at its most efficient RPM (most of the time, peak torque RPM) regardless of how fast the car is going and thus everything on this engine could be optimized to run at that speed, which reduces wear and maintenance requirements. However at the last moment GM revealed that at certain times the engine would drive the wheels directly, probably to prevent some idiots from driving at maximum power and depleting the battery.
The Volt has a planetary gear system that is engaged at highway speeds when the gas engine is being used anyway. At certain speeds, it uses less gas to maintain speed that way instead of generating electricity and using it. When it is more efficient for the engine to supply electricity only, that is how it is done. I don't view this as a compromise at all. It wouldn't make sense to chose a less efficient path just to maintain some sort of purity.
FTA: The battery is expected to last the life of the Bolt EV, and it’s covered by an eight-year/100,000-mile warranty.
100,000 miles is not remarkable for cars made in the last decade at least. Most will go 100,000 miles easily with only routine fluid changes. Granted that may be more than what an EV needs but it's not something most people really "worry" about.
None of my current cars are less than 10 years old and none have less than 100,000 miles; my main family car for long trips is a Honda minivan w/210,000 on the clock and it runs like new and is very reliable. And I only paid 8,000 for it when I bought it with 80,000 miles.
For a gas first approach like most hybrids I think it's a bigger concern. In the Volt since it's just a generator I don't know if the maintenance burden is quite as much of a concern.