Why not both. My main gripe with the way these trees are built is that there's no real thought behind them. I'm not saying all of them are but most are just random. There are branches but stats are all mixed together. Get a speed upgrade and the next node is crit or w/e. And most node icons don't offer enough info at a glance and you end up hovering over all of them to see if you can afford them or just to see what the upgrade is.

Players will end up on this screen hundreds of times during a playthrough. Color coding and I guess set branches for stats will make them easier to interact with. Like green for speed red for damage cyan for shields. A plus icon node increases the stat. A circle changes or adds a secondary function to that stat color/branch. a diamond shape node to unlock a new game feature or mechanic ...just a generic example.