On most bands, US Amateur Extra-class hams are allowed to transmit 1.5 kW because hams are the primary users of the band. On 60m, US hams are secondary users of the band, and government agencies are the primary users. The idea for the 60m band came from negotiations between governments at the 2012 and 2015 ITU World Radiocommunication Conferences, according to Wikipedia. The US government presumably wanted to keep hams from interfering with existing users of the band, so we hams were allowed only low power, channelized operation on five frequencies only, and upper sideband as the only phone mode. (For single-sideband operation, hams traditionally use lower sideband on frequencies lower than 10 MHz, but government users use upper sideband exclusively.)

According to the ARRL, "Our expanded privileges on 60 meters were the result of collaboration between the FCC and the NTIA – the National Telecommunications and Information Administration, the agency that manages and coordinates telecommunications activities among US government departments, the primary users of the band."

The ARRL page goes on to mention that the NTIA expressed concern about possible interference from digital modes, and requested that US amateurs limit digital operating to PSK31 and PACTOR III only.

@MikeWaters answer explains the reasons behind the logging requirement quite well: so that the FCC will be able to estimate a station's Effective Radiated Power when investigating possible ham interference with other (government) users of the 60m band.

On most bands, US Amateur Extra-class hams are allowed to transmit 1.5 kW because hams are the primary users of the band. On 60m, US hams are secondary users of the band, and government agencies are the primary users. The idea for the 60m band came from negotiations between governments at the 2012 and 2015 ITU World Radiocommunication Conferences, according to Wikipedia. The US government presumably wanted to keep hams from interfering with existing users of the band, so we hams were allowed only low power, channelized operation on five frequencies only, and upper sideband as the only phone mode. (For single-sideband operation, hams traditionally use lower sideband on frequencies lower than 10 MHz, but government users use upper sideband exclusively.)

According to the ARRL, "Our expanded privileges on 60 meters were the result of collaboration between the FCC and the NTIA – the National Telecommunications and Information Administration, the agency that manages and coordinates telecommunications activities among US government departments, the primary users of the band."

The ARRL page goes on to mention that the NTIA expressed concern about possible interference from digital modes, and requested that US amateurs limit digital operating to PSK31 and PACTOR III only.

@MikeWaters answer explains the reasons behind the logging requirement quite well: so that the FCC will be able to estimate a station's Effective Radiated Power when investigating possible ham interference with other (government) users of the 60m band.