Isnt that like really memory heavy?
Frankly it doesn't seem like it. It's on a FixedUpdate() so it only updates 60 times a second. At worst a loop can last 30s so a list can be 3600 entries tops. Might seem like alot but it's like 3600 Vector3s or bools or floats, it's maybe slightly RAM intensive but i doubt it has a significant impact on performance.