Thank you for the reply, gazumped.
The letters themselves have the same base height, that's true. But characters in code fragments are wider + those style margins and borders take additional space as well. That make code fragments look unproportionally bigger and, what's more important, lead to neighbour items being overlapped:
Thus, that seems reasonable for me to either decrease margins:
... or font size:
... which is a common practice AFAICS