Flip-out screens can be useful for tricky shots.
We consider a lower weight better because lighter devices are more comfortable to carry. A lower weight is also an advantage for home appliances, as it makes transportation easier, and for many other types of products.
3.has an optical viewfinder
An optical viewfinder (or OVF) allows the photographer to compose a shot while seeing exactly what the lens will capture. OVFs have no time lag and require no power - as opposed to electronic viewfinders, which can drain battery life. OVFs are also better in low light situations.
A hot shoe can be used to attach an external flash, as well as light meters, viewfinders, rangefinders and other attachments.
A flash is good for low-light environments, and can sometimes be used as flashlight.
6.Has an electronic viewfinder (EVF)
An electronic viewfinder (or EVF) is a small display which shows the framed image. Benefits of these over optical viewfinders include: they show more of the image; they can be more compact; it's easier to focus with digital zoom; and they sometimes offer extra info on the display (such as a live histogram).