Roads are a major tool to create gameplay for all ground vehicles. There is more and more ground vehicles on SC, they need specific gameplay and roads are usefull for this.
An example among others : on some planets, you can't go from one outpost to another with a rover because of all rocks/steep hills/mountains. Roads are needed.
Your comment instantly highlights another big SC issue - Gravity.
Yes, higher gravity will often require roads. Unfortunately, with all planets at 1G (and moons at 0.3G I think? Mole/sovapid please correct me), CIG is lumbered with predominantly Earth-like thinking for their gameplay and physics. Is that what a space game should be like? Is that what the BDSSE should be like?
Just think what ED provides in terms of gameplay and immersion with only a single vehicle, the SRV, with gravity ranging from 0.02 to 12 G - jumping, flying, spinning, crashing. Then think of the game design opportunities completely missed by CIG had the entire gamut of gravity ranges been available for their gameplay - the extra player choices, options, loadouts, strategy
and fun. They've restricted players to what might as well be Call of Duty, just because they find physics difficult.
It highlights how much more engaging and immersive the real universe is when we see it against a quite primitive simulacrum. I'm being harsh, as most space games take a similar path, but at least in ED we see a very good galaxy/physics simulator, albeit very light on vehicles for ground-based play. If CIG want a BDSSE, they need to expand their thinking well beyond Earth-like constraints.