In general Black Hat SEO generally consists of bots, scrapers, and other tools that automate a lot of the SEO process. In doing so they may or may not lose quality or perform subpar to manual work. But because most of it is automated the loss of quality is a drop in the bucket considering you can push out a lot more work at a much faster rate. So most of the time you can bury your competition because you can even compete with websites that have a very large marketing budget. There is a post that discusses a black hat technique you should check out.
A lot of people mainly use Black Hat to perform link building this is because building links is probably the most frustrating and common thing people lack and have no knowledge about or even where to begin. Thus they turn to black hat link building we discuss a similar post about black hat links you should also read.
I am not going to go much into detail but I get a lot of people asking me is Black Hat SEO is Illegal? Check out that post for more information.
Some people get slapped with a manual penalty, shadow banned, rankings drop significantly, and other issues when they perform Black Hat SEO. While some will argue that Black Hat is easier and can give huge gains I personally would say that if you don't know what you are doing Black Hat can be a much harder way to rank. This is because it takes at minimum the basic understanding of SEO to perform a good black hat campaign. Without that you may think you aren't ranking because it's black hat but in reality, it's simply because you did it wrong.