Winkly I work on a technical help desk.
We are 24/7 because the people that use our services are mostly military and government and if they can't use our services they could potentially be in serious danger so we have to be there all the time 
We are a small team and usually when we do a shift it's just one of us by ourselves.
My boss was happy to take me off shift because if there's days when I'm late to work for whatever reason (morning sickness for example), the night shift worker would need to stay in work until the 9-5 management team and other support team come in which means doing a 14 hour night shift! (We work 7am-7pm or 7pm-7am days and nights)
Also if I was working a day shift then had to leave for whatever reason or had an appointment and could only do a half day, they would need to get someone else to come into work on their day off to cover me.
It's basically a lot easier for management, the team, and me(!) this way because they aren't DEPENDING on me to be there at certain times to take over from people.
Plus my doctor just wasn't happy with me waking up at 5am to get to work for 7am and not getting home til gone 8pm! And she also said she doesn't think nights are good either.
So I'm pleased... I'm doing Monday to Friday 10-6 and it works well for the team in work as well as they now always have at least 2 people in during the day - me and a shift worker 
I've lost my shift allowance but I'm not fussed. I'm much happier and getting the sleep I need... Waking up at a normal time and getting home at a normal time!
Just realised how long this post is 