Someone more knowledgeable about it than me may comment. But, first I heard it was a safety concern from players regarding collisions at 1st. But now the narrative is out there to encourage more SB’s for in-game excitement.
I think it's a bit of both. Theoretically fewer injuries, but I suspect the bigger motivation is increased offense due to a slightly shorter distance between bases and more area to get around tags.
You can bet that if the majors are doing something that 9 times out of 10 it is an attempt to make the game more exciting in order to make more money. This is almost always trying to get more offense.
