Esmeralda and I are big advocates for babywearing. We own a variety of different slings and carriers - Jack-Jack was carried in one almost every day that he was with us, and had at least one of his daily naps in the carrier for the first few months as he found it difficult to settle in his cot. Even as he got older, if we were out over nap time the only chance we had of getting him to sleep was to pop him in a sling - on my front to start with, and then on my back as he grew too tall to see over. He loved it. From very young, as soon as he saw me pick up a carrier he'd squeal with excitement and crawl or walk over to me in expectation. Andy was also carried - firstly out of necessity on dog walks where we couldn't take the buggy, but he too obviously liked it, he'd come over and raise his arms to be carried if he saw me pick up "his" sling, and would occasionally ask to get out of the buggy and into the sling if we were out.
Neither boy was that fussed about standing still but were both happy to be carried for miles - Jack-Jack arrived in January and I spent hours of my life pacing up and down in the hallway at home when it was too cold to go outside and he was napping. I became quite adept at reading whilst walking, holding the book behind his head as he slept. The rocking motion of walking is so soothing to little ones, it never took him very long to drop off but he'd always wake up the moment I stopped walking!
Being in a sling doesn't have the same forced intimacy of a cuddle, hold or cradle, but at the same time it's fantastic to provide comfort and promote trust, attachment and bonding, particularly for a confused and anxious little person who has recently moved primary carer. There's no expectation of eye contact, or any communication at all, but it really does encourage little ones to engage much more than being sat in a buggy facing away from the carer would do. They're up in your eye line, so can see what you're pointing out as you're talking to them, and can communicate as much or as little as they feel comfortable. Even when on my back, Jack-Jack would be chattering, singing and trilling away to me constantly, whilst pointing over my shoulder to get my attention focussed on whatever he was looking at, or to let me know there was an interesting texture he wanted to reach out and touch. When tired, overwhelmed or over-stimulated, he would rest his head against me and shut out the world for a few minutes or fall asleep.
It was invaluable during separation anxiety or illness (it was the only way we could get any housework done at all at those times whilst giving Jack-Jack the security he needed), and for toddlers and preschoolers, particularly those who are fostered or adopted, it can help when they're going through periods of regression and need extra nurturing. Even though Peter's older, due to his additional needs we still intend to offer a carrier as an option for him, although it will be his choice of course.
Modern ergonomic carriers are so comfy and well designed, there are really no downsides to it. As an aside, although the child's weight is spread comfortably, a long walk is still a great workout for the person carrying which has got to be a bonus! I fully expect to have muscles of steel within a few months if I do end up regularly carrying a 4 year old...