when I was young and starting out, my very smart teacher held his hand over my fingers as I played. maybe about an inch away and so I was not allowed to let my fingers touch his hand. this teaches you how to streamline your movement. (you guys should try this)
for easy slow stuff it’s not terribly important but when you start playing fast exercises and classical pieces you can’t get the speed you need if your fingers are flying high as you see many newer players do.