https://bugs.winehq.org/show_bug.cgi?id=43910
--- Comment #52 from PeterG peter.g.anderson@live.co.uk --- There is a workaround for this.
Modify your shortcut to launch
...../drive_c/Program Files (x86)/Battle.net/Battle.net.exe
rather than
...../drive_c/Program Files (x86)/Battle.net/Battle.net Launcher.exe
This stops the Battle.net Helper.exe crashes from occuring.
Using wine-staging-pba-git-3.10 on Arch