A base in any biome can be cool or good, at least in my opinion

One of my survival bases is in the grassy plateus (the other is in the bulb zone). It's quite nice there.

I have a base in the safe zone on the edge of the grassy plateaus and it's pretty cool, there tends to be a lot of reef backs nearby

It's flat and open. GP bases have a lot of freedom

I build big complexes on the pillars and it looks cool

It's not only open, but most of the grassy plateus border lots of other useful biomes

When I first played Subnautica and was new to it all, I always chose the safe shallows and the sw grassy Plats bordering the grand reef and the sparse reef. But once I had completed the story and completed my first run through I decided to build bases where there are specifically thermal spires or larva holes. Like the bulb zone (only did that once), the dunes (there is a nice hill top right near the Sea Treader path and the Blood Kelp Trench - however 2 reapers love that hilltop - but still) and then the Lost River where the Ghost Laviathian Tree is. Great base location there. That's where my base is with my current playthrough.

I can fit about 12 on the foundation above the thermal vents spires (or less - depends). But basically the base has unlimited energy then.

So to conclude, yeah they're great but not as awesome as the biomes with the therms. Great for temp base until able to descend say to the leviathan egg tree area and set a base up there.

The SW/W Grassy Plats have a very tall rock spire and I would always use that as the location for my base set up. It's near the border with the sparse reef and the bk trench.