It might seem silly to cut the clips down, but it is my guess is that the people that think that, aren't competitive target shooters! And those that enter a speed match in any shooting discipline with 10 round clips, aren't competitive!!!
I shoot a couple of matches a year where speed of reload is important. I have found that by trimming down the length, crimping one end and painting the crimped end for instant recognition that the SKS can be as fast as my M1Garand or my AR 15A2. If you need lots of ammo on short notice on a fired and movement match, you can put 75 clipped rds in a bandoller or 15 rds in each pocket of an M1 Garand web belt, etc. It has taken me a bit of time to prepare clips for 300 rds of 7.62x39 but my SKS is ready to be competitive.
If you want to be competitive, you will make the effort required. If you don't your timings and performance will give everyone else watching you a good chuckle.