I am using the G90 as well. I had no problems at all and it sounds great. The problem with other frequencies is that their use is limited or even forbidden in several countries. For example you are not allowed to use 823-832 in the Netherlands at all. In other countries you need to aquire additional licences (for example Italy), which costs extra money. The only free frequency throughout europe is 2.4 Ghz, thats why it is used for Wifi, DECT-phones and so on.
The G90 has the possibility to display which channels of the 2.4Ghz band are already in use making it easy to select a free channel. I am not sure but I think the other Line6 products do not have this feature.
The situation in germany is that you can use 823-832 for free until 31.12.2021. To my knowledge it is not yet clear what happens after this date, whether you can still use it for free or you have to get a license or if you are not allowed to use ist anymore.