Render Effects Versus Render In to Out

Hi,

In Adobe Premiere Pro cc 2018 does anybody know what each of these options do and how they compare/contrast with each other?

Render Effects seems to complete much faster. I have a lot of LUT colour grading, Neat Video noise removal, slow-mo and stabilization effects throughout my 4K project (95 minutes and around 540 clips - underwater diving related). I am curious on what the Render Effects option does not do that Render In to Out does do and visa versa.

Many thanks,

Graeme