Why can't Side-Quests give more Exp to be a Alt-Leveling alternative?

Like whats the point of Side-Quests anymore anyway. The Exp they reward is low, the gil they reward is low, and its not like they have any important deep story behind them. It's just "kill 3 mobs there because need something from them" and that's it. So for real, why even bother investing time into Side-Quests if they are not worth doing at all? At level 90, with the current Experience Side-Quests provided, you need to do 35 of them just to reach 91 lol.

It's really bad. MSQ gave me so much EXP that I'm already level 100 on the 4th map.
Went back doing side quest with another job to catch up to my main and gave up, it's not worth the hassle, you get more exp killing daily hunts or fates.

This has always be an issue, you can do them while you sit in queue for a dungeon for a little extra, but i totaly agree that they should reward more exp, maybe 500k-1m each