I'm going to suggest it's not about outright accuracy, but manners. If accuracy was the only criteria then 97.4% of people would be better off with a pcp.
The 30 is an easy cocking, accurate, air rifle with a lovely trigger and sufficient power for plinking out to reasonable range.
The stock sizing means it can be shot by just about anyone aged 10-100 all day without any duress or fatigue in a well made package that may well last a lifetime.
In short it offers a lot, to many without demanding much in return.