There is no difference. A /browse/ address is a search with the box already filled in for you. The keyword is taken out of the address, hyphens become spaces, and it is dropped into the search box and run as an ordinary search.
That is why the word is sitting in the box when the page opens, and why you can clear it, add to it or replace it exactly as though you had typed it yourself.
/type/ is the one that really filters
/inspirations/type/floor-plan behaves differently. It sets the Content Type filter rather than the search box, and content type is a genuine filter: every image carries exactly one type, and the page is restricted to it. Everything else you can reach through an address is a search.
So /browse/brutalism returns whatever matches the word brutalism in the text held for each image, including things that merely resemble it. /type/section returns sections and nothing else.
Two words beat one
Because a /browse/ link is a search, everything true of search is true of it. A single common word matches loosely and ranks poorly, and adding a second word in the box narrows the results far more than the link can on its own. How search ranks results explains why.
The page title changes too
Some words have a title and description written for them by hand, and those addresses use it. Anything else gets a generic pair built from the word itself. It changes what your browser tab says and what a shared link previews as. It does not change a single result.
Making your own
Any word works. Take an address you already have, replace the last part and use hyphens for spaces: /inspirations/browse/rammed-earth searches for rammed earth. Nothing needs to exist in advance for the address to open.