An small library for viewing static HTML is nothing compared to a virtual machine and dynamic rendering engine constantly causing unnecessarily high demand on memory, CPU and battery.

I'm an extreme niche, so I recognize that an email client that intends to be used by the general population would need it, but why would I even want to see HTML emails? Those are 105% of the time just marketing bullshit. Emails are either in plaintext with friends/families/clients/people or have a single link that I can copy/paste to verify an account on a website. As it stands, I never download images in my emails anyway. A few sites have tried serving the account verification code as an image and I just won't validate my account if that's the case.

Designed emails using HTML are used by marketing teams - not by people. I don't care to read emails from marketing teams "as intended to be viewed". Show me the email and let me read an email that's just a bunch of plaintext markup.

My laptop has a limited amount of memory, CPU time and battery life.

FWIW, I can read HTML e-mails just fine via mutt in an SSH session. One doesn't need Chrome or Firefox to read them.

Could you go into a little more detail about this setup?

Here is an example:

http://stromberg.dnsalias.org/~strombrg/mutt-html.html

Not GP, but there are browsers that can render and dump HTML to plain text, like Lynx. You can of course also run remote X programs, but that seems a bit clunky.