It might be required in that it's impossible to deliver continuously if changes are not integrated continuously, for some definition of "integrated".

I'm tempted to just downvote you and move on with my life but I'm genuinely curious.

Given that it's meaningless to Deploy something without Integrating the changes, what do you _actually_ mean by "You don’t need [CI]. Stick with CD only."

Are you just talking about testing the changes? Help us out here.

I guess you could just have an unchanging project redeploy itself every hour or so.

What if people push unmerged feature branches, and then the automation just deploys the most recent one?

I'm not advocating this, just to be clear.