Reading email on the Apple Watch isn’t all that useful. I have flicked through the messages and deleted ones I knew I didn’t need, and this functionality works fine.
The watch is a very constrained device, both in size and resources, and many senders have made completely different assumptions about where their messages will end up. Marketing messages are giant images, and I am prompted to view them on my phone. Think I’ll be able to click your link?
As with the Web, we shouldn’t assume how our content will be consumed. Provide a plain-text alternative for your readers.