At the time of writing the query has a small error. The filter is checking for reads and writes, but it should be reads or writes.
WHERE
-- Filter to only show tables that have had some form of read or write activity
(s.n_tup_ins + s.n_tup_upd + s.n_tup_del) > 0
AND
(si.heap_blks_read + si.idx_blks_read) > 0
)
