Until a pitcher reaches the highest levels, there are plenty of other things to perfect before worrying about spin rate. With that said, when competing at the highest level you want every advantage. High spin on a 4 seam fastball produces ride. Ride is the Magnus effect counteracting the force of gravity to make the ball drop less on it's way to the plate. Notice the term is "ride" not "rise", the ball does not go up although hitters sometime perceive that as their brain is auto calculating the normal drop they are accustomed to seeing.
Hitters rely on their brain to calculate where the ball is going to be in space at bat contact based on where the ball is when it's 30 feet in front of the plate. Hitters do not see contact, keep your eye on the ball all the way to contact is a myth. The goal for a pitcher is to be different from the average of the other pitchers that batter has seen. If a pitcher throws around the league average velocity of 92 mph the hitter's brain sees that pitch 30 feet away and claculates when and where (on plane and on time) to swing the bat to make contact. If that average velo fastball has a spin rate up well above the average of all of those other 92 mph fastballs it will cross the plate with an inch or two more ride than the average pitcher. An inch or two above the plane calculated by the hitter is a swing and miss or a pop up.
Changing plane is the new changing speeds. It's new to the masses with the availability of technology to study and practice it with real time feedback. It's not new to some of the best pitchers from past. I have seen old video of a Nolan Ryan interview where he talks about adding ride to his fastball.
ETA: Here is the Ryan clip where he talks about "tight spin" making his fastball drop less than the average fastball.