When I was young I used to play chess with the the old form of notation KB<number> (King Bishop square number), even books used to have the same notation, then later found that everyone was using algebraic, is descriptive notation dead? Why?
Though the previous answers have made some solid points, I think they have not yet given the main reason why algebraic notation has generally come to be preferred over descriptive notation: it is more absolute, less relative, than descriptive notation. What I mean is just this: in algebraic notation each square on the chessboard receives only one name, while in descriptive notation each square receives a different name depending on whether a move by white is being notated or a move by black. This alone makes algebraic notation more transparent, because things aren't relative to which side is on the move.
Consider, say, the g4 square (in algebraic notation). When white moves a piece there, descriptive notation says it is headed to KN4. But if black is moving a piece there, it is headed to KN5. There is just no need to have two names for this square, and it serves only to sow possible confusion in a way that algebraic notation does not.
The two forms of notation you are referring to are called Descriptive Notation and Algebraic Notation respectively. Descriptive notation was the most used form from recent antiquity up until about 1970 in English speaking countries. Algebraic notation has been around since the 19th century, but didn't rise to its current prominence until the 20th century. These days, descriptive notation is considered obsolete, though it is still permitted in tournament play in the FIDE. There are a minority of players that exercise this choice, though. Primarily, descriptive notation is learned and used for reading older chess books which were authored that way.
There are also some other interesting notations in use around the world. Hope that helps clear things up.
To answer your question if descriptive notation is dead, I would say YES. Even though it maybe more descriptive, it can be more confusing for newer players and the algebraic notation is so much more intuitive and simpler to understand. I have read books with the descriptive notation and sometimes I scratch my head.
I used to read chess books in the 1960's. Then DN was the only commonly understood system. I didn't go looking for chess books again until this year 2018. Now everything is in AN. I have a book published in the 1970's bought recently second hand it actually uses both. I recently found some chess magazines in Spanish from the 1990's they all use AN.
For me DN is much more intuitive...not really intuitive ...just common sense. There are two people sitting at the board, so there really ARE two perspectives.