Yes there is. When you edit a video, you're making cuts to the existing stream that has been encoded.
Lossy video codecs (like h264, which most people use when they make an mp4 for online viewing) only encode a full frame image every so often. In between those times, they only encode changes between those images. These are called I frames and P frames.
So if you're making edits and cutting things out, ideally you would have as little image quality lost as possible (depending on your storage space etc).
If you are colour grading, higher bit rate files will handle colour tweaking better (as will codecs with less colour subsampling).
Rendering to lower bitrates makes your video faster to download, and/or faster to start streaming. (Although most streaming services specify their recommended bitrates then make additional versions that they stream to users depending on how fast their network connections are).
Another thought: when you are editing, you generally get snappier performance in your editor if you use codecs that are (mostly? completely?) I-frame based, like ProRes, instead of using h264 for your recordings. These are usually bigger than the equivalent h264 files, but your software doesn't have to generate in-between frames on the fly, so you can scroll around your timeline more quickly.