The one of the problems with ice blasting is storage, even with their coolers it will only last several days so you have to be able to get it and use it right away. The other is compressor to run it, can get pricey renting them and then the fuel to run it. We own our compressor but towing around would be an unneed hassle in comparison to a gum machine.
All kinda prices ice out as a reasonable cost effective method.