I wrote a while back that 90s are back. I started to dig.
19 January 2020 Forbes writes that audio cassettes are hot.
9 November 2019 The Guardian covered the resurgence of cassette tapes.
Benefits: uniqueness, portability, tactile sensation, good audio quality, can be produced in smaller production runs than vinyl with a good price.
With a funky colourful cassette, nice cover print, transparent box and with a delivery one production unit costs 2 € + approx 2 € audio = 4 €. You can sell them for 25€-30€ as limited editions. Or you can just buy blank tapes, record and customise them at home.