Not to mention extremely expensive, at least the petite is.
Oh, I don't know - it depends on how you look at it. It might be a costly initial one-time investment for a relatively small plant, but on the other hand, you don't need to spend a lot on the "extras" (like fertilizer, high-tech lighting, pressurized CO2 injection, fancy substrate, etc.) to keep it healthy, looking nice, and growing.
Then again, with fast-growers under "expensive" conditions, your return is a lot faster since you can propagate and sell them quickly. But you're also putting a lot of time and energy into maintaining/advertising/pruning/packing/mailing/etc. But for some, that's part of the enjoyment, I guess. I felt the petites were worth every penny I spent. I still have one piece that's been floating around in a neglected tank for almost a year, and it's about quadrupled in size. It wasn't a dinky little thing to begin with, either. Then again, I'm not trying to fill the foreground of some monster-sized tank with them. I use it on small pieces of driftwood to aquascape a 2.5-gallon and maybe a 5.5-gallon tank.
But yeah - plant for plant, they tend to run higher in cost.