The primary purpose of the power clean - and all olympic-style lifts - is to develop power. Most of the other exercises in SS are done relatively slowly and build maximal strength. The power clean, on the other hand, must be done very aggressively & explosively, so it develops the ability to deliver force quickly. The power clean has tremendous carry over to sports, since just about every athletic endevour is done quickly & explosively: think of a tackle in football, a slap shot in hockey, a punch in boxing, a jump in basketball. It will improve your vertical jump, sprinting ability and yes, since it heavily works the posterior chain, it'll improve your deadlift as well.
Because of this, the barbell row is a poor substitute. It's a slow lift, so it does not develop any explosive power. Moreover, the muscles it works are completely different: the primary movers in the power clean are the hip extensors (hamstrings, glutes), quads and traps. The primary movers in the barbell row are the muscles of the upper back (lats, traps, rhomboids) and your biceps. Now, I'm not saying the barbell row is a bad exercise - it's a great way to develop the upper back and balance out the bench press - but you should be aware of what you're losing if you choose to do it instead of power cleans.
Don't give up on the lift so quickly. It's harder to learn than the other lifts in SS, but it wouldn't be in the routine & book if you couldn't learn it on your own. Re-read the chapter, watch tons of videos online and practice, practice, practice. It's definitely worth it.