Landscape/ architectural is usually a fairly wide photo, thus one normally uses wide angle lenses and smaller apertures.
but if you are far enough away from the subject, why not ?
but think about this for a few examples.
If you are taking photos of real estate.
You may be able to get a nice outside shot without much of an issue as all you have to do is move further away to frame everything.
But when you get inside you may find that you have a problem, such as you can only get 1/3 of the rooms.
But taking a nature picture of a far off mountain range would be no problem.
Think of what you are taking a picture of.
Then think of what lenses you currently have and at that focal length of 85 how does it fit with your question.
and of course, what do you define landscape and architecture as?
I have an 85, and so far I'm loving it. But truthfully I'm only using it for portrait type photos. period. I have better lenses for landscape and architecture and I know would be a total pain on an 85 if I even could get a good perspective.
When I take pictures of buildings or nature scenes I'm usually at 35 or less. There are times I wish I has something wider than my 18.
Just think of the photos you took of the tall monument, and all the details of the building behind and next to it. How would you set that up if you were using an 85mm vs and 18 ??