@Fried_67 yes, and it would improve over the central rear wheel that takes space. But it would increase the cost, be heavier, more complicated transmission, requiring suspensions, and being forbidden on bike path (at least where I live in France). Three wheels is not perfect but an interesting tradeoff.
By the way, forgot to say this bike is based on an #OpenHardware design! https://vhelio.fr/
Documentation available for free https://communaute.vhelio.org/d/83-documentation-du-vheliotech-version-100-mai-2023 (everything is in French though)
@Fried_67 from the few experimentation I've made, I think every bike is a tradeoff. Improving something brings other drawbacks. So really it's about finding one that correctly fits your needs, but none will be perfect for everything.
The one you've linked seems really cool to travel lightweight, efficient, single person, with possibility to transport groceries in bags. Adding anything will increase weight and/or air drag, but depending on the use case it can be a good tradeoff.