I just made a really big map with the vertical hex grid and it was an issue for me to line it up on Roll20 because the hex grid size is not square. I ended up having to stretch my map horizontally to make the hexes match, which would be a big problem for some maps. But I love how the grid doesn't go over walls or items on my map, so I didn't want to use the Roll20 native grid (just line them up and then hide Roll20's).
If it's possible, could the hex grid be fixed so it's the right size? Or is this deliberate and I'm just missing the reason why?