My youngest's friend has just got her first proper bike.
20" wheel full sus Apollo from Halfords.
I'm not usually a snob about these things - kids usually just get on with it, even if it does weigh more than an old Raleigh Grifter
BUT, the poor lass was really struggling with this thing. She can ride once she's got going, but she can't get the hand of setting the pedal and riding off. Having watched and encouraged for a few minutes, it became clear that she was struggling due to the ridiculously narrow pedals and the very high bb meaning that although she could only just touch the ground with her toes, when sat on the seat, as she pedalled, the her feet were coming up far too high for a comfortable action.
I sat her on my daughters Spesh Hot Rock and she was off as easy as pie.
So, weighing as much as an anchor isn't the real problem with BSO - check out the geometry.