When i started i used black , but then turned over to the white basecoat.
White is quite handy ...
U just gotta work with thinned layers, u never have to thick coats on ur models covering up the detail like that! And it's actually still possible to do things like a drybrush if it's really needed to.
Thinning paints also saves out lots of paint + it doesn't matter if ur paints have gotten dryer a bit and aren't easy to handle - because u have to watter them down anyways..
Also really handy to do shades,.. very fast because the wet paint just runs into those parts where it should be dark. Just paint quick enough so it can run into the grooves.
Very good for doing mass painting. In fact it actually doesn't matter if u just paint a bit over a piece - while the paint is still wet u can pick another brush to just suck up the paint u placed on the wrong place.
Also with the thin layers u might actually barely notice u painted a little bit over a piece that u shouldn't have done. U need to mix less paints.
It's easyr to go darker then to go lighter.
Uhm maybe there are a few more why white is handy. But this might be different for each person what to pick. It was asking me some practise in the beginning since i was so used to the black basecoat but it really helped me improve.
Hope this helps