When testing my emails time and time again I have a few things that always pop up and among those are issues with contrast and not having H1 in email. I like to use background color for my images so they stand out if someone has their images turned off. We also often lead with an image so it makes it harder for us to have an H1 when that H1 should really be the alt text of the initial image.

I need to be able to control the text behind the image - alt text font color, font size, font family, font treatment (B,I,U) and whether H1 or normal text, etc.

This helps with both those issues and improves deliverability and email rendering all at the same time.