Ranalisma rostrata likes a fine substrate, Onxy Sand is the coursest substrate I've seen it do well in. I have it struggling to grow between gravel chunks but it can do so much better.
Lilaeopsis brasiliensis likes a rich substrate, and it is hard to establish from the emmersed growth that they sell in the stores.
Once established, both will run all over the tank just like every other carpet plant. You have to resign yourself to keeping an eye on them and pruning when necessary.
Aquascape? I'm a crypt farmer.
It's a fine line between fishing and standing on the shore looking like an idiot.
That IS an aquascape, it's titled "The Vacant Lot".