There are a few reasons to model to scale. 1. It helps to keep things proportional. No having to scale things to match when you start building a scene. not to mention forgetting to apply scale so it doesn’t cause problems with textures and modifiers. 2. No camera mathematics. People often times forget to adjust camera focal length and if you motion blur you have to adjust the F stop to match the scale of your objects. If you use real world scale there is no need to calculate what those settings need to be to get the correct looking render. 3. It’s a recommendation not a rule. There are plenty of times you may want to adjust scale. Like for instance if you are doing an animation about ants then you want the ants to be human size roughly. Microchip would depend on what your project needs. If it’s just chips in a scene or as a prop then real world would be fine. If it was an explanation video or product visualization then you may want to upscale it.
