there's a key difference.
labels are applied _after_ the message is _received_. Their solution applies the tags _before_ the message is _sent_.
thus they're tagging the thread at the beginning of their interaction with it.
labels are applied _after_ the message is _received_. Their solution applies the tags _before_ the message is _sent_.
thus they're tagging the thread at the beginning of their interaction with it.
You can of course define your own labels, for example:
- https://fastmail.blog/productivity/fastmail-labels
- https://support.google.com/mail/answer/118708
Caveat, labels may be a bit clunky when using thrid-party clients and IMAP.
It is great that you have found a low-tech solution to a problem you have, but you may be reinventing the wheel a little.