Is she worth to raise her to S2? I've read that she's an amazing brawler for a 4* operator, similar to Click for ST casters, or May for ST snipers.
Her set of skills is...unique. You can compare her with Conviction, since her skill is also RNG-based, just not as much as Conviction's. To make her shine at max potential, you'd use her against enemies that does physical damage, attacks at fairly high speed (if you want to make use of her S2), have plenty of support like Shining (to help her survive in case the dodge fails), Aak (to further boost her damage, which is bad against high DEF enemies) and Nian S3 (to boost her block count, granting extra hits per block).
Tl;DR as other brawlers, she's a niche operator that's only useful in certain conditions. Said certain condition includes 1vs1-ing originium panel boosted red weebs, which could be very useful if you don't have Jaye, or act as bait for those spear throwers. If you want to S2 her, sure, why not?
Is she worth to raise her to S2? I've read that she's an amazing brawler for a 4* operator, similar to Click for ST casters, or May for ST snipers.
As someone with an M6 Jackie I can tell you to only raise her if you really love her. Click and May are more reliable and do well in Fungimist while Jackie is niche even within the already niche Brawlers. The RNG of her s2 and her overall low stats mean that it's all or nothing: either she dodges or she just dies. As Rathurue mentioned, she'd also need a lot of support. Seconding Nian because raising her block count means more attacks for her to dodge which could mean more counterattacks thus more DPS. Otherwise, s1 which I prefer has more DPS than s2. With Aak, s1 is better used tho I haven't tried if Aak's friendly fire can trigger Jackie's s2 dodge + counterattack. Personally, I really like her animations. Her s2 looks like she's parrying attacks and her idle animation in combat seems unique I think? I haven't seen anyone else wink in combat.