This is the "pin sweep" method of soldering small SMD (surface mount) IC chips.It is by far the quickest and easiest method compared to individually soldering each pin at a time, or creating a large solder blob over all the pins and wicking it away. Your board will be left with much more burnt flux residue due to the amount of flux applied with this method, however rubbing the board with a cotton swab dipped in Isopropyl Alcohol will remove it quite easily. A the magnifier isn't 100% necessary for this, but is definitely handy to give you a better look at your connections. I've soldered chips like this for years without ever using a magnifier, but now that I have access to one I prefer to use it. Small handheld solder magnifiers are almost as good and pretty cheap. However if you get good and comfortable with this method, you wont really need to bother with one any more except to admire your work.