My analogue mixing desk I use for live stuff only has Jack outputs for the aux sends, but I like to have the versatility to be able to connect my monitors at different lengths with out having to have giant Jack - Jack leads that may or may not get used. Converting to XLR means that I can use the XLRs that I already have with me and if I need the extra length I can connect some together or use the slightly longer ones. Where as with Jack - Jack leads, if your monitor was 10m away you'd need at least a 10m long lead. If it had to twist and turn around a stage full of stuff, then you'd need a longer one. I'd like to point out at this point that I only have a small rig and not a lot of transport space, thus the need for these patch/converter leads. If you're in a similar mind frame as me and just prefer everything being XLR then this is the way to go.