>>83853687It's hard to say why someone's popular because it's all subjective but the how can be explained to an extent.
Given her current popularity she clearly has qualities that are popular, but before properly joining hololive she was seen as nothing but that lady that sings pretty well and does game collabs with Sora sometimes.
She spammed GeoGuessr a lot when she figured out that people really liked watching her play it but if you look at her channel now there's not a whole lot of it anymore because she has started doing so many different things.