short answer is that they train different things
long answer is:
1. smoothsphere hits a fairly similar note to smoothbot voltaic, having both would be doubling up and i prefer smoothsphere to smoothbot voltaic
2. the more erratic movements in smoothbot goated/perfected force you to more actively engage with the secnario. it strikes a balance of almost reactive precision at times which i really like personally, especially since it makes it a lot harder to rely on slow sensitivity to mask poor control. you almost have to play it on a faster sensitivity to keep up with the target and make up that lost control a higher sens can cause through practice
3. the hard to track movements are great for training! ive seen a lot of players who have developed their mechanics primarily through aimtrainers have massive issues with tracking targets at unusual angles because most scenarios are so sanitized in that regard. no hate to the person who posted the clip at all but its a great example, the first movement in that video is 100% possible to fully track if you are familiar with how the feel of aiming changes at far more vertical angles than what most kovaaks scenarios ask of you. i personally played a lot of smoothbot invincible goated when practicing for the finals and i think its why i was able to manage odd angles so well in that game. it was my explicit reason for putting it in season 1 and why im certain that i want to keep a scenario of the same lineage in season 2
i think most of the backlash this scenario has gotten is almost self sustaining at this point. people hear that smoothbot perfected is rng, see any movement thats harder than the rest and dismiss that movement as such without considering how it could be approached in a more optimal way. there are skills at play when it comes to managing overheads. you have to be ready for theme, manage mouse space well, potentially play at a faster sensitivity and recover quickly after a reset. i agree the scenario does have some variance, but its worth it to me to keep it in for the reasons above