It can work, its been done successfully many times and I have done it myself.
However in my experience its a mess and more faff than its worth. Using an "active" substrate is a valid way of doing things and my preferred method. In my experience I find it better to use dedicated "aquasoil" though. This is less messy and "safer" in that you know what's in it.
If you are using under a sand substrate you might want to consider putting it into mesh bags first. This helps keep it in place and stops it mixing with the sand.
Also two things to remember with almost all types of active substrate. Most of them will leech a lot of nutrients into the water at the start, mostly ammonia. This is generally not that big of a deal if you are cycling the tank but is something to be aware of if adding to an existing tank.
Active substrates are also not a bottomless pit of nutrients. Eventually they will run out. However depending on the type of substrate, what plants you have and a bunch of other conditions this will often take a very long time to happen. Even when it eventually does water column dosing and root tabs can be used to take over the job. I have had tanks running for multiple years using aquasoil and light water column dosing with no issues.
You will get better growth with an active substrate then with nothing. However an active substrate is not the only way to do it. Water column ferts or root tabs with an inert substrate will work also.
You also have the option of doing both. I use active substrates and light water column dosing. The active substrate means that heavy root feeders are taken care of and that I don't have to be to regular with my water column dosing. The water coloumn dosing helps out the plants that are more heavily taking nutrients from the water and also help prolong the life of the active substrate. I make my own ferts as well so I can customise to what my plants might need or what might be lacking in my source water.