We wanted to come out with these lines for a few different reasons.
First was for part timers and beginners as bendow suggests. Can't tell you how many new to spey guys we would outfit for their first spey trip only to confuse them and send them running the other direction when we started talking multi tip lines. The same guy/gal had maybe steelhead fished for a while but had handled everything with two rods, one rigged with a dry line and one with the type IV 12' tip or a T200. To keep things simple again for those that choose it, we wanted a option that would allow 2 rods, one dry and one a sink tip. I watched new guys loose their first ever steelhead hooked when they were new to fighting fish with a long rod and not used to loop to loop connections. This line helps with the bump, bump, bump through the guides.
The second was for the little lines and switch rod spey fishing streamers for trout. I never change tips much for this and am stripping the fly a lot. Nice to remove the loop to loop connection when it might enter the guides on every retrieve.
Lastly, I, for years changed tips all of the time, run to run, as needed when fishing sink tips. A buddy and I fished a Skeena system river for two weeks, he fished the same 12' type VI the whole time while I changed tips a zillion times. At the end of the trip we had hooked a lot of fish and I had one more them him. The big difference was he had a lot of extra time to relax and enjoy the scenery. Same thing on other trips so over time I started to fish more simply, spend more time fishing the water and spend less time messing around with tips. Steve Choate and I were discussing how we both felt that we could fish a ton of different situations (especially on certain rivers) with 10-12 feet of T-12 by using different casting angles, mends, length of leader and un-weighted or weighted flies. Turns out managing our fishing was more fun then managing tips. Reading the water and making what you had work was fun. We both liked the idea of a simple line and promoted the idea to the powers that be at SA. Also, in Dec's book he mentions that he mostly uses about 12-15' of type VI for his sink tip fishing and rarely changes during particular seasons.
So this third reason is very different then the MOW approach but I believe both are great tools. I have made and used MOW type tips a bunch (and now have some of the Rio supernice dudes) and will still use them but on rivers where less is more I will use the integrated lines. I think for beginner and advanced these will be great lines. It might be the folks in the middle that want to experiment with lots of things that might not have a place in their "tool box" for them.
On the integrated lines I usually do customize per rod and bulk of situations. Typically this means I am cutting 1'-5' of the tip so I often start with a line a touch on the heavy side if I know I am going to be trimming.
Hope this helps explain the line a bit. I do get asked about it a lot.