Petite size pants definitely adjust where the flare or shaping begins, as well as any distressing, and they typically have a shorter rise. You will really notice the difference in distressing/fading being too low/long if you try to just hem a pair of regular length jeans. And on flares or boot cuts, it just starts to widen too low on the leg and you end up cutting off a bunch when you hem.
I'm 5'2" with somewhat longer legs/short waist. Petites are sometime a bit short, but regular lengths are usually too long. I bought the Logan fit trouser jeans from Banana Republic in both 2P and 0S, and despite the website saying they had the same inseam, the 0S was about 1/2" longer, which I needed - and the slightly longer rise was OK.
The 0S was a tad snugger than the 2P, but not a full size down. This also varies between retailers - always check and compare measurements for Petite versus Reg/S if available. You really just have to experiment.