Humans made trails by walking for eons before roads were envisioned. Maybe for a chariot you need a proper road, but a human made trail is just fine for a bicycle.
I rode my mountain bike A TON as a kid, gave it up for the more "prestigious" road cycling as an adult, but maybe 2 years ago bought a mountain bike to ride with my kids.
My goodness it took about five minutes on a local trail to feel like that same little kid I was back in the day, the feeling of speed, focus, and flow. There's nothing really like it for me, as it puts me square in the moment.
