Does doing well in sololearn increase your chances of getting hired in a software engineering company ?
sololearn reminds me a bit of github, but personally, I haven’t seen any professional code on sololearn’s playground, as on github, so I would say no.
It can if you also supplement your knowledge gained here with other sources.
In my opinion, no. If it seems it does, they may have another source of learning aside from Sololearn.
Sololearn can be used by headhunters. One can search for needed devloper with certain skills and by region. Also it is possible to view users' profiles to get more information.