Adir -
I only bother with the curler if I'm hike/wade fishing. I have hiked rivers with two rods many times, but it's a pain. Once I came back with only one rod. That was the last time for that!:)
You can make up a a few rigs with flies beforehand I suppose, if you are very sure of what you will be using. Personally, I wouldn't be that presumptuous, even on waters I've fished hundreds of times (bad juju).:) But even then, I don't see the need for more than a single rig per style. If you want to change flies, change flies. I wouldn't use it as a substitute for a leader wallet or fly box.
Here's the point by way of a story - You show up to the river and start out on a nice run. You look around, check for bugs and rises (none observable), roll the chicken bones, etc. and decide to try an indicator rig with a couple of nymphs and a little split- shot to get them down along the bottom. After you tie up the rig, you have a decision to make. Which nymphs to try? Perhaps you turned over a few rocks and found a lot of active whatevers to imitate and perhaps you've also had good luck lately with the B.H. Purple People Eater - so on they both go. You fish for a half hour and nothing. Soooo, you decide to change flies but you still want to fish with the same method. You don't need to replace the whole rig - just change flies. Ok, so you finally found the right combo and fishing's been great but you've come to the end of the run and the water upstream is a broad shallow riffle with a nice pool quite a ways above it and who knows what's around the bend. Hmmm... You could walk around it and hike the quarter mile (or more) up to the next run that matches your tackle, or you could change rigs. Out comes the rig storage device (curler) and on hooks the first fly, wind it up and put the butt under the clip and back in the pocket it goes. Now you take out your leader wallet and decide to put on a leader you will probably use for dry flies during the day. On it goes. Then you fish out a bushy dry from your box and hang a nymph below it to fish the riffle. After tons of fish in the riffle you finally get to the pool, but it's dead so you walk around it to find a good long section of boulder strewn pocket water. Out comes the storage device, on goes the leader as before and you put it away again. On this piece of water you decide it might be worth a try to do some high sticking, so you tie on the proper leader from your wallet, a couple of heavy nymphs from your box, and you're back in business. At this point in the morning, you now have three rigs at the ready so you can fish the river completely. No need for skipping sections unsuited to your tackle only because changing it out is such a burden.
Back to the river - above the pockets is another nice run. The tackle you have on is clearly unsuited for it so again, out comes the storage device and on goes the high stick rig. Still nothing's rising, so you decide to tie the butt of the indicator rig to the connector, unwind it from the devise (stretch it) and you're ready to go again - and in less time than it takes to select and change a fly. On the way back down the river you come across the pool that is now alive with rising fish - You get the drill... On goes the dry fly leader but you snip off the bushy dry and nymph combo, add a finer tippet and tie on the size 16 Head Banger Parachute that makes the selective fish go crazy. Heck of a way to end the day.
Now I don't always use it this much. Sometimes I'm in the mood to fish a certain way, or the water type is more uniform, or sections fitted to my tackle aren't that far apart, etc. Also, I do leave all the rigs on the devise and often even my rod strung up (usually, but not always with the last rig I used) if I'm going to fish the same water for several days. Sometimes to save time, I'll even throw the rod under a wiper on the windshield to drive to a different part of the river (my mentors are probably rolling in their graves over this one, they were from the days of pricey bamboo and before no-fault break guarantees):)
Anyway, that's how I use it.
"It's not that I find fishing so important, it's just that I find all other endeavors of Man equally unimportant... And not nearly as much fun!" Robert Traver, Anatomy of a Fisherman