The other problem with this specific test is that an all-zero page is considered to be a valid state. You may consider that a problem or not, but we're quite unlikely to change it, because doing so would create false failure reports. See the mechanisms around file extension.
"A failure mode that produces empty pages will not be detected by this mechanism during normal server operation, but the pg_checksums application will since all normal usage of empty pages is restricted to runtime transient state."