So I have a Streamlight TLR-1 on my nightstand handgun but I have several long guns that have never been accessorized due to my ignorance and laziness. The small potential for a COVID-19 disaster has motivated me to "prep" a couple of the rifles. I just did some research and ordered some slings, mounts, QD style attachments, etc but I'm struggling with the light options. I understand the remote pressure switch but I don't understand why some of the lights are the compact "all-in-one" form factor like the TLR and some are like regular flashlights held on with a mount. These would be for a Ruger PC9 with the Catalyst Arms Kit and an AR-15 with M-LOK handguard. Pros/cons of different styles? I'm leaning towards the Streamlight/Olight price range.