I tried this with my first ... and he is three now and still in diapers most of the time...
I completely skipped it with my second baby.
Elimination communication did work for us! My son peed and pooped on command when he was 3 weeks old, 3 months old and 10 months old. It was too time consuming for me to stay consistent. I was so tired, hormonal, mood swings and still healing from labor. Sometimes it was only 15 minutes in between wet cloth diapers. You're supposed to keep the baby in a dry diaper at all times so as to teach them to be uncomfortable in a wet diaper. I abandoned the practice when I had a huge pile of diapers to wash and was behind on all my housework. (I have become a lot more disciplined in chores since then!) Also it is hard to juggle between breastfeeding and pottying when they are that young.
I don't think elimination communication (diaper free baby) is a problem, but I think my lack of experience with potty training skewed by perceptions. I didn't know what I was doing or what to expect from a baby. I thought I had to teach my child to use the toilet and not just model it for him. I am still learning to let go and wait for my son to be ready 100%. He has delays in speech so that definitely causes miscommunication in many areas. Although I still wonder if it would have been easier for him to learn before he became an opinionated 2 year old and later even more opinionated 3 year old!
Although I think introducing the potty chair early is a good idea.
I have heard that in traditional cultures around the world, children are potty trained much sooner. I remember seeing a chart comparing countries and ages on it. It makes sense to me that a child who is outside a lot more and surrounded by more siblings and cousins and not encumbered by carseats, buckles, buttons, etc. would learn sooner.
I would say if you want to try it, then first search your heart and find the true reason why. Then make sure the rest of your home is in order first before attempting it. It should be something that creates a deeper connection with your baby rather than an element of pride or added stress. Part of my reason for wanting to try it was because I wanted less laundry. But also to avoid having a late bloomer. Well...
It also is easier if you have a routine at home. I would often hold my baby while he napped and I would sit on my phone, forgetting to eat or do anything else productive.
Oh the luxury!
Babies are just like toddlers. They will hold urine if they are sleeping, but they will go as soon as they wake up. So you have to be fast!!
I remember hearing my baby wake up at night and I was so tired that I would reach out a hand to shush him back to sleep (we co-slept), although in the back of my mind I knew what he really needed was to use the potty. I was too tired to wake up enough to do that. Night time was such a blur with my first. My second baby was a breeze at night after she slept 8 hours straight at 6 weeks old!!
My midwife encouraged me to try elimination communication because her experience was that it was much harder to start with baby #5 than baby #1. She encouraged it as a way of communicating with my baby. I felt like it was more about training me to give him a "potty opportunity" than communicating with him.
The best advice for whatever age you decide to introduce it at is to always be prepared with a potty chair when out of the home. Toddlers are often scared of big public toilets.
If anyone wants more specifics I kept journal entries of my experience that I can share to help people know what to expect.