Not a huge advantage, but I'd say mostly range and flexibility. You may want to put the tag farther away than you could hear an alarm clock, if you want to go t

Not a huge advantage, but I'd say mostly range and flexibility. You may want to put the tag farther away than you could hear an alarm clock, if you want to go to another room. And you could customize the alarm so you're guided towards a different tag every day of the week, without needing multiple (or any) alarm clocks.