In this case, "cuspidata" and "difformis" as not accepted botanical names are only auxiliary names to term particular cultivated strains of B. heteroclita, without taxonomic value. So they are in the same category as other auxiliary non-latin (and IMO necessary) names in quotation marks such as "Pantanal" or "Red", or even "Micro" and "Mini", similar to cultivar names. I mean, in this case preferring them not because they are Latin names, but because they were there first, and are unambiguous as each is apparently used for 1 heteroclita strain only.I agree, I much prefer using the Latin names to avoid confusion.
True aquatic is somewhat difficult to define, there's a number of plant species not classified as true aquatic by the botanists because in their natural habitats they don't grow in water the most time, nevertheless they can grow permanently submersed in tanks. E.g. Staurogyne repens.Are these ferns true aquatic plants? I have read that they do poorly over time when left submerged.