The early Betamax recorders didn't have a timer on them. Plus the tapes were super short. So if you had a show at 3pm you wanted to tape, you had to be there at 3pm to push the record button, then be stuck with only 90 minutes of recorded content.
The first Betamax recorder sold in the US was the LV-1901 which included a 24 hour timer.
The first standalone Betamax VCR was the SL-7200 on which the timer was a $45 optional add-on.
Also at the time people were already buying wall socket timers for their reel-to-reel tape decks to record the radio, these would also work with a Betamax deck. https://www.youtube.com/watch?v=XbNgbtZJAcU
