Sanity Check Please! Boss wants to block customer list from SEM ads, and have email/SMS target past converters.

I have managed PPC in-house (retail) for quite some time - over a decade.

To me this is mind-boggling, and it's honestly weird coming from him.

He thinks we could save $money on marketing when email/SMS is free. Rationale is that most of our SEM customers are 1st time customers, and that email/SMS will carry the weight of retaining those customers.

I'm told I'm being negative and not a team player when I say that this is a bad move (never really got the chance to elaborate) and that I need to be more open to new ideas.

My thoughts:

Returning customers using SEM have a much higher CvR and lower Cost/Conv

Many returning customers do not even use email to repurchase - they go straight to the search bar.

Many customers that do read email, will search later and not click in from email.

etc...

Am I crazy?