scene_update_pre & post, while used as hacks, actually provide a useful pipe into blender's update logic that would make some specific scripting tasks impossible. Clever usage allows operators to be run out of context, let's a dev run asynchronous requests and smart threading, as well as code injections. Until there is a proper proposal for replacement handlers, scene_update_pre/post could be left in 2.8, as at least to my knowledge, there are several addons and plugins in production environments that take advantage of them.

Operator requires an execution override to work properly:

When called from the Dynamic Context Menu (spacebar), it works just fine

Do you have any settings enabled in the Color Management tab? If you are using Film, RRT, Log, or Raw color management settings, or have color curves enabled, or you are using one of the built in camera filters, Blender will crash upon rendering your scene. (These settings can be found in Scene Properties, next to the World Properties button, underneath the Color Management tab)