It’s really easiest to just keep everything AC until the point of use, putting a transformer and a bridge rectifier in most devices is a better solution than needing switching power supplies everywhere to convert DC voltages (or wise options like linear regulators).
Switched mode power supplies also have EMI to deal with due to the higher switching frequencies, an AC transformer runs at line frequency (50/60Hz).
Switchers, for all their complexity, are pretty damn clean in terms of output and input PF correction. Even in audio and sensitive analog applications where dumb supplies were preferred have been replaced by switchers. A good design goes a long way and it's unfortunately easy to design junk switchers because of the complexity involved.
Yes, and cheaper to build!
You can achieve the same efficiency with DC and AC do not directly effect efficiency across the line contrary to popular belief. It is simple about what the voltage across the line is.
AC was in because it allowed us to build transformers to up and down voltages to provide efficient across the line.
Nowadays, we can build DC transformers with Power MOSFETs which are cheaper, and more efficient then there AC counter parts (old [magnets and inductors] and new [You can do AC transformers with MOSFETS with some extra steps/components]).
Additionally, since most consumer appliances first step is to rectify the voltages most build in the past two decades are DC compatible. Additionally, newer ones could then drop the rectifier stage and become cheaper and more efficient.
In fact there are higher loses with AC power transport (specially in long distances) due to the parasitic capacitance of the lines, that’s why some countries use DC power transport lines now.