I have done that for years and basically it is fine until you make a mistake. One day I bought a sword one of the ones that reaches the top and floats leaves. In the end it messed up everything. Also did the same thing and then put in a bulb nymphaea or something and the same thing happened. Basically just a shop light, a fluval canister that I always neglected and a pretty low fish load.
I have two ten gallon tanks right now that have no CO2 running in them. Tap water that I just treat with Amquel and java fern, java moss, driftwood and a few crypts. Sometimes I add some kent micronutrients. One filter has some floss in it, and the other has a piece of sponge. They are both hang on the back. One has no substrate. There is some alternanthersa in there that is just wedged between some driftwood.
One thing I learned over the years is that sand always becomes a problem. I always liked it the best but it always became a problem. I stopped using it.