While that works for having completely separate actions, it wouldn't work for having job-specific targeting macros. (Like the example where I want the targeting to do drastically different things for healer and tank, where healer would be target's target while tank would be <2>)
Nor does it address the other issues about skill queuing and visibility (without needing to assign it elsewhere). Adding further to the inefficiency regarding queuing, while yes your macro would indeed fall down, you may not be aware that every line even if ignored adds a small delay. For those pushing for efficiency, having so many alternate versions would be unacceptable, especially on weaker machines where the macro delay is actually affected by hardware delay.
Furthermore my suggestion wouldn't affect your current usage of R3 as while my picture of "before and after" may be slightly misleading, I do admit, I am not asking for macro 98 and 99 to be replaced, but rather 2 new options added so that those who currently have #98 and #99 do not need to redo their set ups if this change were implemented. You could still use your macro, but the rest of us who want something different would have the choice to do so.
Thinking beyond myself, maybe someone would like to put their pots on R3. It is currently not possible to assign an item usage to a macro.