Other areas of preferences are less useful.
If you're using a theme which uses bitmaps for widgets, you won't be able to see the button colour changes nip2 usually uses to indicate state. This option adds three small LEDs to each row which indicate select, busy and error.
By default nip2 file browsers show only VIPS images. If you find you mostly use (for example) JPEG images, you'll save yourself a few clicks on every file operation by switching this option to JPEG format.
You can set the save options for the various image formats.
If you running Linux and have a capture card that supports the V4L interface, you can capture straight from the card into nip2. Set the capture options here.
The paintbox normally tracks all undo operations. This can chew up a lot of memory, especially for flood fills. Reduce the number of undo steps to free up some RAM.