What about the effects on branding / user perception of the message? While the first short email feels ok, the straight-shooter 'Hi, I can see you signed up, what do you want from us?' version feels awkwardly impolite.
I find it still obvious that it is an automated message and the attempt at 'being human' makes it even less appealing. This kind of metric chasing most likely results in dark patterns and subpar experiences.
Every company should find their balance between brand and optimization. Amazon will implement practically any change that shows an improvement to some KPI, while Nike would rather preserve their brand image at the cost of, say, lower checkout rates.
I find it still obvious that it is an automated message and the attempt at 'being human' makes it even less appealing. This kind of metric chasing most likely results in dark patterns and subpar experiences.