I don't fish the same stream frequently so I don't see the benefit of them in my fishing and considerable benefit to not cluttering up my vest with another box.
Just like with nymphing you still have to adjust for water depth, speed, clarity, etc., so making up a new rig every time is both more likely to be apt to the situation and less likely to fail due to wear. That is to say you still have to (or should) adjust the length and X size from the dry, change dry or nymph patterns or both, change how long the tippet to the dry is, etc.
I also know that if I keep a box with tandem rigs, I will regularly pilfer that box for patterns in non-tandem situations, whether wet or dry.
Tippet is cheap unless you use flourocarbon so just make them as you need them.
Just my .02.