For some time I didn't really understand the real differences between these two sighting systems. I've found this article to be quite informative and figured it's worth sharing (and one less open tab in my browser and/or bookmark that I'll never find again).

Although the article does start with finding the 'best', it's really just good information - so don't get hung up on X vs Y.

https://gunpros.com/red-dot-vs-holographic-sight/