Steam has made several changes to their Loader that make it much better than it was. The only problem is that the old displayu of games in the library was easier to work with on a UHD display compared to the existing design.
First the new downloads is easier to drag the game into the active downloads. Now doing that does not distupt the current game update.. With upwarrds of 1000 games installed the dowmloads are very active.
Next is the improved library manager. Now it shows games sorted by size and players can move several games at once now. The bulk moving games is ideal for those with mutiple SSD and hard disks. At present larger SSD capacity is rather expensive so most games have their old SSD in the second slot and the new one for Windows in the primary slot.
Storage is not a problem with 9 hard disk bays but when the SSD is full. This new manager means that 2-100+ games can be moved to anther location. Not many gamers have those 100TB SATA SSD units in their rig for obvious reasons.
I do not install games on the Samsung 980 PRO 2TB, the Intel 665p 2TB is used for games instead. This way downloading games over and over when I have to reset Windows is avoided.
The new Steam loader now makes it quick to move games to anther location so now there is no longer as much reason to avoid the system volume. Still having more free space on the system volume does make it more efficient with 25% utilization.
Steam needs to consider that gaming may be using a laptop with a limited resolution display while others have a 4K panel and beyond. For this reason the design choices must span a wide range of LCD displays.