Masks don’t fully prevent smelling the environment because scents waft right through the gaps.
BUT, with the entire airflow modified, it’s surely the case that a mask inhibits our olfactory sense.
We don’t tend to appreciate the importance of smell because we’re rarely consciously aware of it, but every animal has been smelling for hundreds of millions of years.
What are we missing, on the functional and aesthetic side?
Nobody knows.
There is even a section in Plato's Timaeus above facial coverings hindering the sense of smell, as I recall, in sort of an ancient atomic theory discussion!