They’re not absolutely necessary, just nice to have. It helps automate things and they’re designed to do the finishing really well. But you can do fine with cheap options too
The printer comes with a finishing kit that has two containers that you can fill with IPA, fill one enough that you can submerge your print, wear gloves and swish the print around in it before dropping it in and letting it sit for about 10 minutes. After that, take it out and swish it around again. Ideally you’d put more IPA in the second container and then you would rinse the print in that second container which can further get rid of residue (the first container of IPA will become cloudy with resin residue and doing this can rinse that off).
For curing, I use this cheap method: Easy UV Cure Box for under $30