Last year, as a test, I removed all of the comments off a WordPress blog I own - Half were auto-generated, but a lot were genuine.
Around 1/2 of posts had comments, and most had a minimum of 10.
Site traffic fell from around 1,800 organics/mo to under 500.

So, as I always say, we have to ask ourselves as SEOs:
- Does Google detect comments as UGC like other tools already do?
- Do comments count to your overall content count or as part of a "sub-content" or as content at all?
- Do comments create renewed page freshness?

In my eyes, comments are seen as UGC (User Generated Content) by Google, as even @ahrefs can detect comments as UGC. Google splits them from the body content and uses them as -
A) Trust Signals
B) Anti-Spam via Comment Analysis

They can also work in your favour in terms of triggering freshness due to it adding additional, new information on to the page which Google's base level spider reports the page to be re-evaluated.. Explained in as many words as you can fit in a tweet.