I do mostly agree with you, but I feel the irresistible urge to play the devil's advocate for a post. My apologies.
As much as they might look 'correct' for the environment... There's still something incredibly fun about finding non-aquatics that can end up loving life in the riparium. As a gardener as well, there's also very practical reasons for me to put non-aquatics in my tank as well.
An example of this is coleus, a stunningly colorful foliage plant that is extremely easy to clone by putting stem cuttings in water and waiting for them to root. Usually it takes weeks to get them to the point where they've developed enough roots to plant in dirt. However, by putting them in my tank instead, with nutrient-rich, circulating, oxygenated water, I can have coleus rooting within 3 days. In 7-10 days, they've developed enough to plant in dirt. Though only a temporary part of the tank at best, they really are an eye-catching addition.
I've accidentally multiplied other plants in the same way- a butterfly bush cutting I meant to use as an art study, and a few houseplants that were near death. There's something incredibly fun about noticing that a plant is doing unexpectedly well. Equally exciting is seeing a plant in a place you don't expect it to be. To each their own though.