why not improve real life rather than sleep time
I will answer this directly as well.
There are 168 hours in a week. Say you spend them this way.
56 hours of sleep
60 hours of work (and commute time, and self improvement)
20 hours of eating
=126 hours or 42 hours of free time. and let's face it, you probably dont do the first 2 as often as that.
So say you want to spend time with your friends and family and have a personal hobby. 6 hours a day for all that to fill up your calendar. I doubt that you use that. I am guessing that you spend 3 hours a day max with friends unless you are a teen-college kid. Leaving you 3 hours a day to veg in front of he TV and/or computer.
Here is my straight up schedule.
56 hours sleep.
35 hours work
25 hours study and church functions
7 hours with daughter (minimum of 1 hour a day)
14 hours with wife (minimum 2 hours a day with her)
10 hour minimum with friends and family
Total 147
11 hours for hobbies, which I have a lot of, so to only have 11 hours is rhard. Note that this isn't rigid. I often spend less time with wife and more time with friends, and I often study less in order to hang with friends and family, or sleep less to spend time with wife or daughter. but my 11 hours seems pretty strong. If my schedule gives, it gives to something else. So to ask why I don't work on something in real life is a little crazy. I spend all day every day on real life. If I can increase my 11 hours a week to more because of changing sleep to fun time, I will.

Also, it is a hobby that might help real life in the future, so fun now, fun and help real life in the future sounds like the way to go for me. I simply love LDing, but I will not sacrifice any relationship for it, I sacrifice hobby time only. And in order to get better at waking things and keep hobby time working i have learned to speed read. This makes studying more intense and book series able to get through with such short time.

Life is about balance in many ways. You should look for your stress vs work meter and see how productive you can be without becoming a crazy person. I am a very stress free person, and I can credit that to balance and a laid back person and my God (I won't talk about the last one since y'all prolly don't care, if you have questions, then PM me).
Laid back doesn't make sense because laid back people normally like more time to chill out, but it is actually cool because since you are chill, you can really work more without. Letting things go easier, working harder without letting t get to you.
Balance is more about balancing everything on your stress level. So I do as much for my self improvement as possible, because stress will make you lose things and forget things that you wouldn't have had you spent less time on it and had a better balance. It is better to study the day before, sleep the night of, and do a short review the day of, rather than to study the whole day before, night of, and day of a test.

So it isn't "work on LD instead of something that could help me." It is "work on LD or some other hobby."