Many of our aquarium plants are amphibious marsh or bog plants in their habitats. That means they can grow submersed or emersed. Some species use both depending upon the wet season or the dry season. While emersed is faster and thus less expensive for nurseries, you should plant them either emersed or submersed, depending upon whether this is an aquarium or terrarium/paludarium.
The switch from submersed to emersed and emersed to submersed is not rapid. The plants in many cases have to produce a different leaf structure depending; emersed plants are generally less rigid than emersed, and emersed leaves need to be thicker to avoid the loss of water, something that submersed plants do not need to worry about. The leaves can also be quite different in their shape. Sword plants in the genus Echinodorus show all of these characteristics very obviously.
If you intend keeping these plants in an aquarium, do not grow them emersed unless you intend selling them.