ok, quick lesson on why charging through your computer USB ports is SLOW.
Most daps are USB 2.0, Mini and Micro USB are designed to run usb 2.0. the only DAP i know of that uses USB Type C is the Shanling M1 and i´ve seen devices like the Xiaomi Mi4c that have a phisical USB C port connected to a usb 2.0 logical interface so thats not a strong indicator too.
PC´s will top out at 550mA when plugged in to a usb 2.0 device, add to that a dirty little secret... that motherboard you bought with 8-10 USB ports and you can add another 8 through headers ? Its really got 2-4 usb ports and each is hubbed to 3-4 ports.
and that 550mA figure ? its per PORT, not per hub. so if a origin port is hubbed to four, and you have a bluetooth dongle sucking up 200mA, theres only 350mA to go around for the rest of the ports on that hub.
Most decent chargers have chip that tells cellphones and other usb devices that they can use more power, therefore the sony can charge at 700mA instead of the 550mA usb 2.0 tops out at.
now this is 700mA at 5 volt (or 3.5 Watt/hour)
and we know Watt/hour = Volt X Amps/hour
So the sony is charging its lithium battery which is usualy between 3.8v and 4.2v off a 5v current. you would actually have to do the equivalent amps at the specific voltage the batter works at... Or like any decent manufacturer actually put how many W/h the battery has instead of having us stupid people do the math between different voltage.
Just a small additional detail. Some usb chargers arent up to spec... i had this lenovo charger that i thought was the dogs bollocks (if you excuse me being crude) it was the fastest charger i owned, until i actually checked what made it so kick ass with a usb analizer, it was feeding devices the correct amperage, but at 5.4v instead of 5.0,
Now a good usb charger... under load might go to anything between high 4.8 and a low 5.2, but this was a high 5.4 (5.48 if i recall correctly) and that was too close for comfort and could really shorten the lives of your devices. i keep it aside as my "emergency" charger for when the battery exploding is a acceptable risk