and the sound capabilities were not as advanced as the SID also used in the Commodore 64.

From a practical user's point of view, three tangible features the C16 lacks are a modem port, a VIC-20/C64-compatible Datasette and game ports. Commodore sold a C16-family-specific Datassette (the Commodore 1531) and joysticks, but the pins are identical to those used on the Commodore 64, so it