True, but his claim seems to be that what was changed was an integer used to describe the boundaries, not the precision of the positions themselves. The positions themselves (in default CryEngine) are 32-bit float. To be honest, map boundaries would probably be expressed as a float too, so the concept of changing to 64-bit to be able to "describe a bigger box" is kind of senseless.
Waaay upthread I think I linked to an idealistic design of a positioning system that used fixed point. I agree that it would be better, but I think retrofitting CryEngine with it would have been much harder and more error prone. I'm also not sure if it might spanner up the conversion between frames of reference, eg local grids etc. You might end up swapping from float to int and back several times.
)I think if you're "rolling your own" engine for one specific game, then anything goes. Though the "standards" nerd in me would want to make things as easily compatible as possible with external stuff like 3d models & meshes, textures and all the rest of it.
The benefits of using an existing engine, such as CryEngine or UE4 are pretty obvious, you can use standard tools to create content and assets, the vanilla editors are pretty good, and so long as you don't want to do too much that's not available out-of-the-box, development is relatively painless and good results can be achieved quite quickly (see original SC Kickstarter video
