Just about every v$ view in the database is a facade over an underlying memory structure, not a physical table. So for (most of) those views, we need to protect that structure when you query them to avoid chasing memory pointers that change whilst the query is running - you could head off into all sorts of memory areas.

So yes, we protect those structures with latches, for example, I ran this:

select name, gets, misses
from v$latch;

declare
  x int;
begin
  for i in 1 .. 100 loop 
    select max(objd) into x from v$bh;
  end loop;
end;
/

select name, gets, misses
from v$latch;

and compared before and after figures. In my case, I took over 3million 'cache buffers chains' latches. It's the same reason we have some v$ structures designed particularly for monitoring performance that can hence be queried more aggressively, eg v$sqlstats, v$active_session_history

So with all v$ views, querying should be done in a "sensible" manner where 'sensible' depends on the object in question. For example, v$session is typically a small, relatively fixed size object, so querying it frequently would be much less problematic than querying something like v$sql or v$bh, especially in these modern times of near terabyte sized memory areas for the database.