It's got moderate replayability if you enjoy the core game (I do).
That is, it's good to come back around to after a few months or even years away to play again. But, definitely not the sort of thing I'd instantly restart after beating it.
Funnily enough, thanks to the map screen warp glitch in the original Link's Awakening, that version had a lot more replayability because you could sequence break the entire game and all dungeons, so you would beat it one way and then restart, map warp your way to the northeast corner of the map, and start playing from there. I must have played the gameboy version 4-5 times through in a row when I was younger just checking out all the glitched dungeon rooms, deleted or inaccessible content, and sequence breaking.