Currently the Owlbear Egg is a versatile item. You can sell it, you can eat it, you can use it for the quest. Just like you can think the broken shards of Mourning Frost are trash and sell them. Turning the egg into a quest item would severely limit its use to only be a quest item - and if you never decided to solve the quest this way, it would just sit uselessly in your camp inventory without even the option to sell it. Like the goblin drawing of the Chosen, the book from the dude who took a tumble down the cliff of Ethel's back door, or all those broken Moon Lanterns which we never use because Gale prefers to cleanse the circle instead of creating the Shadow Lantern.
I don't mind that it can be used for Long Rest. You are shown the items you use for dinner after all - and the new upgrade at least managed to sort things by size, so larger portions are listed first. But I think Beaky should get the same dietary restrictions like Crimson or Tara and only should be able to be fed with raw meat or fish. Does our little fellow really chomp away 40 camp supplies a night btw?