https://elandi-rj.github.io/vmf2box/made a site that generates a box command from a vmf file for you instead of having to manually type them out
to use it in game with more than a dozen box commands you will need to place them inside a config file that you bind a key to exec.
best use case I think is for any map that has annoying regen triggers
limitations:
starts to lag with a lot of boxes
the boxes fade over time
pressing the key to exec 800 boxes a couple times in a row can make you crash