That's a fascinating article. It does mention that they weren't particularly useful though:
_Over Japan, bomber crews soon discovered strong winds at high altitudes, the so-called jet streams, but the Norden bombsight worked only for wind speeds with minimal wind shear. Additionally, the bombing altitude over Japan reached up to 9,100 metres (30,000 ft), but most of the testing had been done well below 6,100 metres (20,000 ft). This extra altitude compounded factors that could previously be ignored; the shape and even the paint of the bomb mantle greatly changed the aerodynamic properties of the weapon, and, at that time, nobody knew how to calculate the trajectory of bombs that reached supersonic speeds during their fall_
Note that this wasn't due to trouble with calculating groundspeed, it just turned out that figuring out where a bomb would hit requires way more than just altitude, groundspeed, and position. Still, the fact that it's complicated is quite relevant here, especially since the bomb was dropped with a parachute. Somewhat counterintuitively, bombing accuracy was a pretty big driver behind a lot of the nuclear arms race, and improving accuracy is why bombs increased in power rapidly up to the 60s, then gradually declined.
_Over Japan, bomber crews soon discovered strong winds at high altitudes, the so-called jet streams, but the Norden bombsight worked only for wind speeds with minimal wind shear. Additionally, the bombing altitude over Japan reached up to 9,100 metres (30,000 ft), but most of the testing had been done well below 6,100 metres (20,000 ft). This extra altitude compounded factors that could previously be ignored; the shape and even the paint of the bomb mantle greatly changed the aerodynamic properties of the weapon, and, at that time, nobody knew how to calculate the trajectory of bombs that reached supersonic speeds during their fall_