You asked
Is the leica sl typ 601 worth buying used?
Here is what the site says about that.
From Leica SL (Typ 601): Leica SL (Typ 601): A mirrorless camera by Leica with a 24-megapixel full frame sensor, announced in 2015. Leica's first full-frame mirrorless body, with no in-body stabilisation. Specs - Maker: Leica - Mount: L-Mount - Sensor: Full frame, 36 x 24mm, crop factor 1.0 - Resolution: 24 megapixels - Stabilisation: none in the body; use stabilised lenses for slow shutter speeds - Announced: 2015 - Type: mirrorless camera Focal lengths on it Full frame ...
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.