Any reason you wouldn’t want to use them as your road shoes? I mean, apart form the easy on features, is there anything else that distinguishes them from “proper” road shoes?

Usually better/more ventilation for drying off wet feet.

Chilly as a result!

Usually better/more ventilation for drying off wet feet.
Chilly as a result!

Pretty much this. And the fact that some of the cheaper ones aren’t as supportive with their closure style.

Sometimes they have a single closure mechanism like a Velcro strap.  This can make it more difficult to get a snug fit around the whole of your foot – the tri show will be tight in just the one place.

Both as above.

Chillier, but great for hot summer rides.

Not quite as snug a fit.

I wore some Specialized Trivents for all my road riding for quite a while. They were perfectly fine except I needed Belgian booties in practically all conditions.