You can connect the camera direct via USB and mount as storage without the app. Though it’s only USB2 speeds lol. The app allows you to transfer over wifi which is dumb because it only lets you do that with jpgs. It won’t transfer raw files wirelessly. I just pull the card and use a fast card reader.

I personally only use the app as a bluetooth remote shutter release.

But many people also use the app to auto geotag their photos, as not many canon cameras have built in GPS.