Whilst these are some of the cheapest XLR / DMX cables available this is certainly not indicative of their quality. These feel better built than numerous more expensive cables that I have used in the past.
Treat them correctly (i.e. only pull on the connector not the cable!) and these should last for years. Easy to coil up for storage & transport, and available in a whole ton of different lengths.
These are literally that cheap that I have brought a load of these at all different lengths so I never have to make do with using a longer cable than necessary- helps keep light trussing looking tidy. It also means I have plenty of spares.
Whether they would stand up to the rigors of long term stage use I'm not sure, but for mobile DJ & home use these are pretty much perfect, and cheap enough to have plenty of spares.