Its just a balancing act. The value here is you can scale up this form of energy storage at a low cost - I am talking GWh scale. (I am assuming that this article is backed by good research. IEEE-Spectrum is a sorta the public face of the peer-reviewed technical journals from IEEE.)

Any it would have to be compared to batteries and H2 systems that are both extremely capital intensive and likely dont have the same "scales of efficiency". Batteries certainly dont- there costs are basically linear, and H2 is has its own funny equation (adding storage is cheap, but the balance of system costs are extremely high.) Also, there are pretty significant losses in both batteries and H2 storage.

The current thinking for H2 is pretty interesting. The idea is you setup the H2 system next to a NG plant. Then use renewables to power the inefficient electrolyzer when power is basically free. Store it, and then co-fire it at 10 or 20% with the natural gas. So, it does have its application, and it could become quite common. But it isn’t a stand alone system like what they are discussing here.

It also worth noting that we do have a lot of industrial heat recovery systems that may be able to take advantage of incumbent geo-thermal equipment. So, there may be some real savings here.

At the end of the day, this wont be a silver bullet. But it may have a significant role in cracking the GWH scale energy storage that we really need.

The thing you have to remember is that in many areas, there is so much excess renewable energy that its basically free. So, it doesn't really matter if its less efficient.