They seemed interesting, and I came away with two main observations:
1 - A game can take a very very long time. Turns might even take days or weeks on particularly elaborate ones. Thus there is a major time commitment during which you must leave the game out and setup for an extended period of time.
2 - My first thought when encountering these was "why aren't they just using a computer?". But I quickly learned that the ability to spread out a map, that might be many square meters, and see everything happening on it at once, without having to slide a monitor's viewport around (or zoom in and out) has a number of massive advantages -- and (at the time I was looking at this) there's really no display technology today that can replicate this.
I feel like both of these observations have changed significantly with the advent of cheap, high-resolution, networked AR/VR headsets. I don't think I'd want to wear one entirely for the length of time a game might take, but we're much closer now to having truly digital versions of this that eliminate many of the downsides.