Users don't need to 'Choose a server' and aren't confused on signing up and know how to use basic features like search and can find the users that are who they say they are. For BlueSky, two months with this growth in adoption is very early days.
But we will see what happens when the invite system is lifted and if the users are retained enough on BlueSky and what the users on Twitter will decide to move on to if Twitter gets 'worse'. But it seems that BlueSky so far is winning amongst the rest of the other failed alternatives that have tried for years to challenge Twitter.