Then I could do parts outside of the cabinet like my frame and stuff.
Sure, you can abrasive blast with a pressure pot outside, but that's a different kind of mess - and other issues if you're not somewhere that is warm and dry most of the year.
Brent just did this video:
Jump ahead to the 21 minute mark for the laser cleaning. To clean something like that, you'd either have to disassemble it to get it into a cabinet, do it outside with a pressure pot, or spend the money to take it somewhere with a big enough cabinet/room to do it.
EDIT: Also that it is focused. With abrasive blasting or vapor honing you're going to get everything covered with grit or water. So back to disassembling things that you don't want involved in the process. With this you just don't do that part or area.
After his shop fire, I can certainly see why Brent spent the money on this although, as Austin says, you're into a similar range of money with a big boy compressor and abrasive or vapor blaster. You're probably in a different market than a Harbor Freight compressor and blast cabinet if you're considering this, vapor honing, or similar options.
ANOTHER EDIT: At the 48 minute mark he starts giving his thoughts on using the laser cleaner and does some trials on different materials and offers some tips he's discovered so far.