I never saw a DisplayWriter.
I could have sworn there was a commercial attachment/accessory for the Selectric that turned it into a normal printer. This was around the time where the daisy-wheel typewriters hit the consumer scene (Olivetti and Smith Corona had ball typewriters for a while too) and a considerable amount of them also had Centronics interfaces available as attachments.
Nothing beats the Selectric. Much faster than a daisywheel, and they had that lovely mechanical staccato sound that was music to the ears. The sheer number of them that are still out there (and working) is incredible.