So I was testing the snapshot out, and did notice that the crosshair reach appears to be a bit broken.
Made an example here with some mobs. Apperantly you can reach them up to 5 blocks in length. Some of them can be interacted:
Shear the Sheep works with that length.
(Milking the Cow in that length won't work dou.)
You can also interact Trades with the Villagers and Wandering Traders.
Wolves/Cats and other mobs that can be tamed and riden on like Horses will also work.
Is this true in survival mode? Creative mode already has increased block reach, so maybe this could be considered more concessions for creative players