I do this. I have a nice plastic pallet on pallet forks, with four U bolts clamping pallet to forks. I operate the machine by myself and use a ladder to get up there. My machine has low hours and lives indoors, and I'm a pretty light load compared to the machine's capacities.
For me it's a question of judgement. I'm pretty likely to survive a 6' or 7' fall, and I'm only doing this something like 4 hours per year, and I think the chance of falling is quite small. I think the other risks in my life (driving, illness, falling off the roof when blowing out the gutters) are much larger than this one.
Nearly all my seat time involves lifting or carrying loads other than myself, so if I burst a hose some day it is very likely to be while carrying those loads. And it is quite unlikely I will ever burst a hose.
I think taking a job working on such a platform all day every day for years and years would probably turn out OK but I don't like those odds. I think it's good if industrial work standards wouldn't allow this. But, then, I think I'd rather not take a job driving professionally, as I'm a bit timid.
Definitely on us to make our own judgement about this.