This is absolutely needed for those on HubSpot Starter because you can’t create custom fields - AND you can’t create HTML table formatting into the source code, what’s up with that?! I’ve never seen this missing from an email editor - you can easily do this in ConstantContact, iContact, Pardot, Marketo, Zoho, ConnectWise, and more - even in Salesforce itself!
Using an image is an alternate but, the more images you have, the more spam filters you trigger. Ugh.
I worked in product development for many years - let’s get this on the development roadmap.