Affiliate-driven reviews introduce a major bias into the author's opinion, as they have incentive to speak more positively about platforms that are likely to pay the most.
And email marketing platforms pay a lot in affiliate fees. Just scanning some of the recommendations, if someone signs up for MailerLite through this reviewer's link, they'll pay the reviewer 30% of that subscriber's fees forever.[0] I wouldn't be surprised if the reviewer's top pick is coincidentally the platform with the highest-paying affiliate program.
The thing that really woke me up to affiliate-influenced reviews was the 2017 article, "The War To Sell You A Mattress Is An Internet Nightmare."[1] The reporter figured out that top YouTube mattress reviewers just gave positive reviews to whichever company paid the most in affiliate fees, and when one company lowered their fees, the reviewers retroactively downranked them for contrived reasons.
[0] https://www.mailerlite.com/affiliate
[1] https://www.fastcompany.com/3065928/sleepopolis-casper-blogg...