My experience is that any time you have a tool that is suppose to be capable of doing more then one thing, it usually doesn't do any of those things very well.
If you want a lazer cleaner to remove the rust and paint, and your thinking about getting one that will also do welding/cutting, buy two tools. One for cleaning, and one for cutting/welding.
Even one machine for cutting and welding may be pushing the chances of that one machine doing both duties well. At least the cleaning processes are similar operations to each other. Cutting and welding are pretty different, but a few tools (like a torch) do both OK.