https://bugs.winehq.org/show_bug.cgi?id=39403
--- Comment #47 from tt_1 herrtimson@yahoo.de --- Yes, it is possible to browse the steam store with your linux browser and to "install" the game in steam properly after you bought it. For this you have to copy the steam:// link which the store offers you and adapt it accordingly to your settings.
env WINEPREFIX="~/.steam" wine C:\windows\command\start.exe steam://replace_with_proper_command_offered_by_the_steam_webstore_to_install_your_application