Thanks for the reply everyone.
In my case, it looks like there is no real drawback then, since what used to happen is:
SELECT a,b,c
FROM table
WHERE clauses
OFFSET x LIMIT y;
followed by:
SELECT COUNT(*) FROM (
SELECT a,b,c
FROM table
WHERE clauses
);
(notice the lack of OFFSET and LIMIT)
and both of them were replaced with:
SELECT COUNT(
table.id) OVER () AS total_entries_count, a,b,c
FROM table
WHERE clauses
OFFSET x LIMIT y;