One that is the same size as the rabetting bit will have as much mass and probably have about the same cutting attack but a smaller straight bit like a 1/2" will be under more stress in a large cut. Well, AFAIK for MDF 18mm has been the standard for at least 2 decades, whilst plywood is almost aways nominally 3/4in (19.

This innovative stepped rebate router bit cuts a double-step on the back of picture and mirror frames in a single pass for holding the glass and a backing piece. As with a dado, one of themost common ways to cut a rabbet is with a stacked dado head cutting set on a table saw. We’re using a rabbet to attach the back panel to the bookcase, but they also have a variety of joinery applications.Our three-wing slot cutter router bits allow you to cut a range of grooves, rebates or biscuit slots. These radius grooving router bits are great for custom sign making, veining, lettering and edge work. The depth of the cut is determined by the size of bearing fixed to the base of the bit and due to this, rabbet bits normally come with a selection of different sized bearings so that you can cut a range of different depth joints. Chamfer or bevel cutting bits are also available in a range of different cutting angles including 11.

Due to this rounding bits also normally include a range of different sized bearings that can be swapped out depending on the depth of cut required.This 1/2" set includes all eight bearings to make 1/8”, 3/16”, 1/4", 1/2", 7/16”, 3/8”, 5/16”, and flush trim.