There are three types of safe opening:
1) Destroying the safe with an angle grinder
2) Drilling the safe with the possibility to repair the safe afterwards
3) Manipulation of the lock or picking it with no need to repair anything on the safe besides making perhaps a new key
Then there are companies which are general purpose locksmiths or safe dealers which do type 1 if the don't know shit or type 2 if they have some knowledge. And there are companies specialized in safe openings, which do type 2 (generally or with electronic locks) or type 3 (with mechanical locks where possible). A type 1 opening is shown here
https://www.ndr.de/nachrichten/schleswi ... paltig.jpg and here
https://www.ndr.de/fernsehen/sendungen/ ... 65120.html (it is in German, but the language of the angle grinder is international). It is really sad, that people pay for such jobs and even worse jobs, because they do not know what a good and a bad opening is.
I think a lot of profitability depends on the area where you work. If there are already a lot of other companies the profitability is lower, because you have to share jobs, but if it is just a side business it can help you make more money than what you otherwise would have. Specialized companies are not that many here. My impression is that you can live from it quite well, but it is a lot of work, a bit like assembly-line work in awkward positions, lot of driving from one safe to the next and you can earn more as a locksmith with doing larger projects.
Another specialized task is the opening of deposit boxes in banks. Probably also not bad, but difficult to get the jobs.