(a) You're making assumptions based on rule of thumb, I'm talking about real world usage: your points make sense in theory but don't necessarily reflect reality

(a) You're making assumptions based on rule of thumb, I'm talking about real world usage: your points make sense in theory but don't necessarily reflect reality (b) I'm talking about a narrow & specific case. PB may outperform JSON in most cases but I'm very specifically referring to browsers where JSON is native (& highly optimised) whereas PB is provided by a selection of open source libraries written in javascript. So that domain heavily favours JSON perf-wise.