I mean so long as the fish isn't needed for any quests or something, a super rare fish sounds cool, actually?

As someone who loves fishing in the game, that's neat. More like that please, for other jobs, too!

Plus let's not forget it's still on the quite easy/fast side of things to get, comparing actually difficult stuff like say, getting Insane in the Membrane in WoW back when it was first added, legendary precursor drops in GW2 before the rate got upped or even worse, many of the epic spawns in early EQ1, like the Enchanter stuff where you needed a Monk to essentially camp stuff days and nights for you to be ready to ideally IRL give you a ring that your 20-50 people need to log in and you should start the phone chain. (none of these were or are good designs, it's for illustration)

Those were all bad because they were needed for something. This just being fluff for bragging rights if you did actually manage to be by chance in Tuli when the stars align? That's kinda neat!