The shape resembles a bullet, and they fly just as well as one - a name that is well deserved.

They pick up very little weed and are far less prone to snagging. The line also runs through the straight bore with less friction than it would through an eye.

Bullets are available in tungsten, lead, brass and steel. Tungsten bullet weights perform best, though they are also the most expensive.

No - on well-finished weights this is not necessary. Very cheap weights can have sharp edges that damage your line, so it is worth buying quality products.

Yes, and there are real advantages to doing so. The risk of snagging is reduced, you can swap a blunt hook quickly, and the flexible connection between hook and weight often leads to better bite conversion.