I've bought a couple of these to connect pedals from different manufacturers (e.g. EBS and TC electronic), as the pedals can be different sizes and/or have their inputs/outputs in different places. obviously only works if pedal in/out is on its side ;)
well, for me it works perfectly, the pedals are positioned tightly together and in a straight row, i.e. none of the pedals is considerably higher/lower in the row of the pedalboard. might not work for all pedals out there, so do a little research about pedal dimensions and some the math before buying.
in my particular situation (wanting the pedals strictly straight in one row) I don't think I could have saved any more space between the pedals if they were connected with cables that have flat plugs - two of those plugs next to each other are probably thicker, or just about the same width s this connector, once plugged in.
nota bene, I bought a couple of straight connectors from the same brand, these work great to connect pedals from the same manufacturer.