I’d find it very handy to have a syntax shortcut which automatically links to a specific ticket within the same Zammad installation. E.g. #12345# could link to ticket 12345. This could be used in notes and replies and is not the same as linked tickets. However since links to other ticket can too easily be removed (see Non-unconditional removal of links), this could also be used as a more safe method to link to other tickets.
Writing the absolute ticket URL into notes and posts is not a good alternative, as the base URL of the ticketing system might change.