...Some owners do use substrate, but I'm sure they would agree that it is a lot more work!
This is true. I only have substrate in one of my enclosures, and getting the ecosystem right was annoying at first. Now I have plenty of "life" with bugs that eat poop and dead leaves in there (worms, springtails, earwigs that I discovered yesterday). I got some soil that doesn't seem to mold either.
It's really neat to see all the little tunnels that the bugs make, and there's tons of things going on when it starts getting dark. That's always when the cleanup crew arrives!
I have the substrate with my Ellioti, who has a VERY planted (probably over planted, but he's really shy) enclosure and has no chance to get any dirt, not that he goes anywhere near the bottom... The dirt stuff I have absorbs moisture well, and seems to release it quickly, as I keep having to actually water the plants planted in there or they die. I would never consider this with my veiled though. Every time she gets something new, she HAS to taste it and try to eat it. She's also a lot larger, and more likely to eat the pieces which are too big for my ellioti.
If you want substrate, you have to provide draining, and make sure everything is planted enough that your chameleon won't accidentally reach the dirt. It also varies from chameleon to chameleon. Some would love to try some yummy black/brown substance, but there are some who never go lower than the middle of their terarrium. If you don't want to take the risk, best remove it. Your cham will be fine without

And you can make things look nice, even when your plants are in pots!
::EDIT::
Those bugs you saw...what colour were they? If they were white they MIGHT be springtails... but it's hard to say without a picture or more description. I'm also unfamiliar with the kinds of bugs that can randomly pop up in the USA
