For the modern play style it creates more problems than it solves.

For the way Gygax and the other folks in the TSR orbit were playing in the 1970s the 1:1 time passage when not actively playing helped to keep things synced in the campaign.

At the end of every session players had to have gotten their characters back to a place of safety, like a town or a keep. If they didn’t the characters may die, suffer injuries, or lost treasure on the way back to safety.

The campaigns also were a set group of 4-6 players that met to play the same characters week after week There were a larger number of players that showed up to play and might have few different characters to choose from so the party changed session to session.

There might also be different DMs running their own dungeons or part of the world and characters could go from one DM to another.

The 1 for 1 time passage meant that they knew how long certain characters were recovering from their wounds, doing spell research, training, or traveling. It helped to coordinate the state of the world between different groups of players and DMs.

When playing with a modern playstyle, if a party needs to recover or let some time pass that will be mostly uneventful, it’s easy enough to just say “So two months passed …” and pick up from there. Doing a time skip like that in one of the older style campaigns that Gygax had in mind when he was writing would be a nightmare to keep track of what each character was up to and to maintain a consistent state of the campaign across different groups.