Filter caps in SMPSs can cause enough fault current to flow to trip your RCD if you have enough of them. The same with MOVs for surge protection that comes standard in many devices now (they are also capacitors when below the threshold voltage). With so many devices using SMPSs and having built in surge protection, the only sensible way forward is having RCBOs instead of MCBs on individual circuits. AFAIK, this is already becoming standard in some countries.