I think you’re describing exactly what I show on the left with 1/2-4/5. The problem is that the laser cut has a thickness and so you have a laser-wide gap between the pieces. For some things that might work, for others if you need a more exact fit you have to kerf adjust.
Try it out, it can be much easier to understand with a practical experiment.
@marmak3261 might be able to phrase all of this a bit better, he has a lot of experience with kerf adjusting, his post about a compass rose was very instructional early on for me.
@jbmanning5 also has a ton of practical advice on this given his puzzle work.