I'm curious, too. I'd much rather carry my purse around. Can't stand things around my neck.
Let's see how you like to carry your purse around when you take a snooze on the deck...will someone be watching it for you? What if you want to ride aquaduck or take a dip in hottub or pool? Will you LOVE your big bag then? It's not impossible, but it is MUCh more secure around your neck. You have to pop it out constantly to do anything. I also never bring my purse on the excursions, even WORSE than having it on the deck. But I could bring my ship card, credit card and a few bills of cash with me and stick it in my lanyard around my neck.
Also, ours were STYLISH! I show you. (Small in the photo though, but they are fancy gold or silver metal chains with various colored beads:
https://fbcdn-sphotos-c-a.akamaihd.net/hphotos-ak-ash3/935034_116193968582862_1435368860_n.jpg)
There were very few instances where we brought bags with us (for valuables anyway, not towels etc) and when we did (around the ship), they were back pack purses so we could keep track of them.
If you have pockets, that's ok too (but my coverups and dresses never/rarely do). The only time I didn't have to wear it was the Pirate wear! I had a big hip belt with tankard and pouches, so they carried my card and incidentals.
It also is REALLY easy to set your card down in the room and not put it BACK in her your purse and than realize you are locked out of your room. (That is assuming that Husband or someone else stuck their key card in the light switch and then took it with THEM. You may not have put YOURS in the light holder, assume you put it back in your purse, and than wala, you don't have it. That is a bummer. Now you have to track people down in your room so you can get back in...) Whereas if you look down and see a BLANK lanyard holder, well then you know you aren't leaving with it...
I bought different chains for all 4 of us in our group, and we wore them almost all the time and loved them. Handy dandy!