It's a premed delusion that you can have to have your app in as early as possible.
Submitting secondaries without an MCAT score is insanity.
Secondaries are often a tax on the hopelessly optimistic, if not pathologically clueless.
EXCEPT - this year, some schools, like the CA schools, have specifically instructed applicants to NOT wait for scores that have been delayed due to COVID, and that, while admission decisions will not be made without them, IIs very well might be issued without them. In that case, assuming someone is reasonably comfortable with how they are doing in practice, waiting for a score when everything else is ready to go might actually be insanity, since it might just cost someone on the bubble an opportunity to interview.
If this were not the case, why would the CA (and other) schools be doing this???? They are doing it so that they don't get slammed with a bunch of applications in the middle of October, which will totally screw up their workflow. Assuming applicants follow direction from the schools themselves rather than us here, IIs will have gone to people with otherwise excellent applications who insanely submitted secondaries without a score while people taking advice here are still patiently waiting, and who will by definition be competing for fewer slots when their secondaries are finally received.
Of course, it is ALWAYS better to have a MCAT score before applying. However, this year, under these unique circumstances, it might be worth taking the risk of following the specific guidance provided by certain schools, and accepting the possibility of maybe being a reapplicant, if someone has an otherwise excellent application and a reasonable expectation of receiving a score in line with the school's requirements, in order to maybe receive an II in August as an alternative to waiting for a score to be released in September or October.
This is just the opinion of an inexperienced premed who has been following this obsessively for around a year who is not burdened by the experience of how things have always worked for the past half century. YMMV.