Indeed, this lens has been very popular among commercial photographer who are doing full body portrait, in the particular market, this lens is often considered as premier portrait lens.
I will not go into the wisdom of using 35mm as a portrait lens since it is really up to the judgment of individual photographer.
In general, there are two type of people using this lens for professional purpose.
Former is people who are shooting architecture/landscape and latter is people shooting portrait.
While I do not use this lens much for commercial landscape photography purpose, I used this lens a lot for commercial portrait purpose.
For the particular type of model...very often female model, I often do the model interview with this lens alone to determine how well this model will work with my project.