As small as it sounds, the collections feature is a big deal for me. Particularly in my line of work marketing food and drinks.

Unfortunately sharing your collection with someone is a point in time. If you update your list, the link doesn't update to reflect that, nor does it update their collection if they've imported yours.

What I would LOVE to see is Apple Maps developing it's own little social circle of recommendations with your contacts and or other Apple Maps users, instead of shitty Yelp integration. Sharing collections, keeps a pointer to your collection as manage it. I suspect this is where it's going to go(hopefully).