I used a buggy until about 3.
Learning to walk is not an overnight thing, it's a slow process. At first they will crawl 99% of the time and occasionally take a few steps, but they will be faster and more confident crawling. The first steps to walking 100% of the time process takes about 2-3 months. By about 6-8 weeks in they are usually walking 80-90% of the time and by that point I get them shoes and let them walk outside.
However, even new confident walkers ~15-20 months are slow, they stop to examine every stone and weed and dog poo. They trip over easily if there are obstacles. They don't understand instructions yet and they vary in how "steerable" they are - some are like a dog that will follow with an enthusiastic "come on, this way!" but many are like cats and will go in whichever direction THEY fancy with no care at all for what you want to do, nor giant buses/trucks thundering past.
So I differentiated between taking toddler for a walk (short distance, no particular destination, maybe a very local park - e.g. ours is less than 5 mins away adult speed) and actually going somewhere. The buggy is for transporting them - when you need to control which direction they are going, when you want to walk at adult speed, when you need to keep them away from hazards (roads, water, rubbish etc) when you expect them to nap, when they are tired, when they are having a tantrum. Depending on where we are going, I might let them walk when we get there - walking to a park, yes I'd get them out and let them walk around. Picking up sibling from nursery, maybe although probably not. Going to the shop definitely not unless I have a second adult to follow them around.
They were about 3 before I could reliably ditch the buggy and have them follow basic instructions, have a little bit of road sense, hold hands, not get tired, basically walk at a normal pace (a bit slower than adults but not toddler slow).