I don’t really feel like an OT purist, but there’s just so much great shit about the OT that I genuinely think gets missed if you don’t consider it in isolation, forgetting the PT and ST exist entirely.
What stands out to me in particular is the sense of wonder and power around the Force. If you watch the prequels or sequels first, then Yoda pulling the X-wing out of the swamp is a less powerful, less magical moment, and Palpatine conjuring Force lightning in RotJ doesn’t leave as much of an impression.