A pretty big reason straight from George’s mouth as to why changes were made from release to release, or in this case from the unaltered original theatrical version to the 1997 Special Edition version (as found by doubleofive):-

George Lucas: “So yes, the Special Editions were a means of researching and testing what I was going to try to do on this film. (re The Phantom Menace)”

^ https://twitter.com/doubleofive/status/1151316503314227205

I know it has also been mentioned elsewhere on the site, but I thought it was also worth a mention in this thread too, given the topic being discussed in here.