Scans account for 75% of this game's total in game counter, and since some objects can only be scanned once, and if you miss it it's gone forever, such as the lone Missile Door at the beginning of the game, it's not exactly a fun category. You'd have to stop so much to scan things, whereas in All Items or Any% it's just barreling straight through the game no holds bar
It was discovered during the trial run phase that the game shows 100% achievement in the results even if the large missile amo in the "Item" category is not obtained (the "Item" category may be allowed to be missing one item). Just to be safe I even included in the video proof that I finished the scan with the ship after I finished the run. I think there is room to consider if this should be included as a category rule.