They already have a list of LTE bands that will work depending on if you buy the Europe or US variant. That list is only for the Gemalto PLS8-US and PLS8-E. There is another Broadmobi BM818 module as well.
For the US, AT&T, Verizon, and T-Mobile support the 2, 4, 5, and 17 LTE bands that work with the PLS8-US.
All of Europe should be supported on the PLS8-E.
The BM818 mention doesn't specify which version. On the FCC's website, there is a manual that lists bands 2, 4, 5, and 17 so at least it will work in the US.
When buying any sort of unlocked phone, you usually have to check all of the bands with your carrier just in case. When you buying a phone from a carrier, they have already done all of the work for you in terms of checking compatibility.
It would be much better if they could simplify the chart to display country, network and the variants of their phone. This is a very common problem with phone retailers and why I never order internationally. This is the final checklist item before I pre-order.
And if just some bands are supported, may that affect network speeds? I don't think this phone is going to very successful because at the very least they should have made some interactive guide where you simply can select where you live and it will simply display if it will work for you.
Focus on the high-level person if you want. But have a simple version so you extract as much money as you can.
If Midwestern farmers could get a functional phone exchange working with a few handsets and fencing, we in the modern era shouldn't have more personal setup work than they did.