High power to size (weight) efficiency, very fast start up/shutdown and you can run them on a variety of fuels, quite cheap (relatively to other fossil fuel plants, fuel cost obviously varies on where you live) - if you use the waste heat (since they produce a lot) to produce steam and drive a steam turbine with that, you get quite an efficient cycle (though I'd be surprised if that is what they are building).

They scale up as well, most of our (UK) fossil fuel plants for energy are Combined Cycle Gas Turbine's (since we took coal completely off the grid a few years ago), so not that rare.

I suspect the reason they are doing this though is it's a well understood technology that can be built with a reasonable level of manufacturing capability at volume fast, the "hardest" part is the turbine blades which is likely the bottleneck so this is probably a smart move in the sense that's likely the thing there will be an immediate demand for.

Doubly so if you can get the EPA to look the other way with it's fingers in it's ears while humming.