The larger matrix heats up slower. A cooler sensor has less noise.

It is difficult to make a lens brighter than ~ F0.95

The F1.8 in a micro 4/3 camera collects as much light as the F3.6 in the FF.

The smaller matrix heats up faster and is more noisy.

My problem with full frame is that is has too shallow depth of field. In a low light environment, you typically set your lens to wide open to maximise light. But will get too shallow depth of field so you will need to step down and increase the ISO. With MFT you have more depth of field from the same f-stop, and can use less ISO boost and still depth sharpness. So the ISO noise argument isn’t really valid unless you want 5cm of sharpness depth.

Um, isn’t that exactly what I said in my post? Bit lost by your comment.

Sorry, micro four thirds does exist. Your post is pedantry in the extreme.

Micro Four Thirds is actually a silly name. It really should be Mirrorless Four Thirds, built around a 4/3-inch sensor but with a shorter flange distance (with the mirror removed) and thus somewhat more compact than the previous generation of 4/3 systems. I believe it was the first iteration of ‘mirrorless’ cameras, long before Sony/Canon/Nikon/Fujifilm followed. (mirrorless being defined as interchangeable lens/system cameras rather than point-and-shoot compacts or ‘bridge cameras’ which of course were also mirrorless)

The current meaning of “Crop factor” is based on 35mm focal length equivalence i.e. that a 50mm lens is somehow considered ‘normal’. Anything less is considered wide angle and anything more is considered telephoto. So for MFT with 2x crop factor, 25mm is a normal lens and for APS-C, 32mm is a normal lens. Agreed, fairly dull topic.