It depends on personal preference - some parents choose reusable nappies because of the environmental impact, or disposable ones because of cost and convenience.
There’s a lower upfront cost of disposable nappies and they’re more convenient to use - you put them on your baby and simply dispose of them after they’re spoiled, a good choice for parents who don’t have a lot of time on their hands.
Reusable nappies will be cheaper long term, but they can be time-consuming as they will require washing each time they’re spoiled.
Some parents like to use a mixture of both, for example using reusable nappies at home, and the disposable kind when away from home.