well, different people want different things 
personally, i’m not really a eurorack user. but i have a random handful of euro modules that don’t see much use. they would see far more use from me if they were on the floor and wired up for normal line level with a bypass switch. (for eample i have a teletype, two analog delays, and a DIY fuzz/filter thing, which would make a nice pedalboard addition.) indeed, i usually use aleph in a pedalboard with some kind of true-bypass effect loop, and with more pedals in line with the channels 3/4 IO. right now, i would probably buy an empty Patch Box if they were still made. DIYing one is more trouble than it’s really worth to me.
i do have plenty of buchla modular. an obvious and deliberate quality of the buchla system is that audio signals are normal line level and can be arbitrarily patched in and out of other things. always seemed pretty sensible to me.
scott from harvestman is a friend. i remember when he was doing the black locust and other feedback-oriented modules, and using them in a setup with a very small rack, with bass/guitar/amp and some stompies, seemed extremely fun for industrial/metal sounds.
i was about to say, “aagh! don’t blow up your k-mix!”
but looking i see the inputs are rated up to +28dbu. so you probably won’t smoke it. still seems like a scary precedent, patching +10v into anything digital that expects line level. in any case the k-mix output is limited to +2.6dbV, which is a small fraction of the eurorack range. (but maybe you are talking about using some line-level eurorack interface module.)
