The old 'bike in a crate' scenario. Sure it's a cool thing for 5k but what exactly does one do with it? As long as it remains unassembled in the crate it's a unique piece of motocross history. Once removed from the crate and assembled it's still a unique piece of kit and worthy of being on display in a museum. The third option is to ride the thing where you'd pretty quickly discover:
1- That it's not a particularly good bike.
2- That parts are bordering on impossible to find unless you live in the suburbs of Prague, and even then it'd be tough.
3- Your unique NOS unridden collectors piece is now just another used CZ now worth half of what you paid.
In reality these 'new in the box' bikes come up more often than you'd think. A friend in the USA has a still boxed AJS 410 Stormer and another mate here in Sydney once had a new, unridden CR250M that he eventually raced, wiping 60% off its market value on its very first lap. The above CZ is, in reality an expensive conversation starter that will eventually become a pain in the arse dust catcher taking up the space in the shed that should be used for bikes that you can actually move from place to place, let alone actually ride.