The more random the pattern the more reactive your control has to be. With a completely fixed pattern you just train your muscles and forget it. With a random pattern you adjust on the go.
So far the added randomness in Apex is still very mild. E.g., the tilt of R301 pattern varies slightly between sprays and the top half sometimes goes less to the side. The R99 received really little randomness (it should get much more and some pattern randomization like the R301) - the pattern is exactly the same every time, but the horizontal tilt differs a little. Go in to the training room and do a few sprays from the same starting point and you'll see the slight variation. So you still do the same S pattern, just need to add a slight compensation left or right sometimes. In reality though, if you don't change anything, you won't feel any difference, unless you're good at sniping targets at 100+ meters with the R99 (which shouldn't happen at all, in the first place).
Imo completely random horizontal recoil (e.g., like in PubG) is A LOT better and requires much more skill (when the gun jumps sideways out of nowhere, you have to react to it and bring it back in, not just do it as a learned pattern), but I guess Apex is not aiming to be as hardcore.