You asked

Is the fujifilm gfx100 worth buying used?

Here is what the site says about that.

From Fujifilm GFX100: Fujifilm GFX100: A mirrorless camera by Fujifilm with a 102-megapixel medium format sensor, announced in 2019. The first 100-megapixel GFX, with a built-in vertical grip. Specs - Maker: Fujifilm - Mount: Fujifilm G - Sensor: Medium format (44 x 33), 43.8 x 32.9mm, crop factor 0.79 - Resolution: 102 megapixels - Stabilisation: in the body - Announced: 2019 - Type: mirrorless camera Focal lengths on it Lenses frame like 0.79 times their ...

From Buying used: Buying used: Cameras and lenses are built to last, and many photographers upgrade often. That makes the used market one of the best ways to afford good gear. A body that's one or two generations old is often most of the camera for a fraction of the price.

Quoted from this site's pages.

From these pages