> Why shouldn't a website have an official reddit account from which they post? Especially when the circumvention is so trivial?

Because it would remove ad revenue from Reddit if any company could just post ads without paying.

Sort of, people can still catch on by going to the reddit page that lists all the submissions by domain name and may notice trends if it's like only a specific type of submission being done repeatedly, like for example using OPs domain you can see all the posts linking to his domain https://www.reddit.com/domain/saaspegasus.com/

That's true, you have limited options when it comes to Reddit submissions no matter how crafty you are.

But comment promotion is unlimited, and for that reason, that's where my mind went.

For example, some of my highest volume referrals from Reddit were comment-replies I left on some submission that became the main result for, say, "best <product> 2020". People trust comments and they have weirdly-good authority in the SERPs.

Right now if you google "battery life of <product>", it parses a comment I made on Reddit in 2018 and shows in the instant-answer box.

I know I'm getting off the thread's rails. Just thought it was somewhat interesting.

No way with getting off the thread’s rails. This is a good point and your examples of How strong some of your comments are for referrals is helpful.