She's complicated, her plight is interesting, she has a cool backstory and relatable depth, she's beautifully tragic, her motives and warrior like qualities are admirable, she's both the show's best antagonist and much needed antihero, and she's usually right about everything. What is there NOT to like? She's the bamf Vegeta/Brock Samson character of the show but with a sad twist. Being a hot amazon with an amazing design is just a bonus to everything else that makes her best gem, and the only thing stopping her arc from being perfect is that she didn't get a happy ending.
Also Jasper has WAY more chemistry with Steven than Lapis does, her relationship with Steven is better than ANY of Steven's relationships with the other gems because it's built on respect and comradery, not Steven acting as her therapist or her sucking him off because has Pink Diamond's gem and talk no jutsu
and try being less gay