Click rate of html email: 0.3%
That's very low and yet the result was, loudly claimed in bold, that the plain text one had 3.3x more clicks than the designed email!! Also, the opened rate is within the margin of error and therefore insignificant. I may not be a data analyst, yet I look at the analysis and think to myself, "eh?"
And with the open rate that significantly affected, all other metrics would be skewed as well.
I don't know much about this space, but 1% of people seems really, really low if it's people who have actually asked you to email them
I should update the post to include a few more recent examples from other companies, that had higher baseline metrics but still saw improvements from simplifying their emails.
I agree with you, but suggest that the frustration is with the broader issue of "noise" pollution created by advertising incentives.