How can I play Starcraft 2 under Ubuntu 16.04 [duplicate]

Yes there is, and I'm amazed on how easy that is. You can do all installation, download and configuration with flatpack (a similar installer like Ubuntu snaps).

This is the tutorial for Ubuntu:

sudo add-apt-repository ppa:alexlarsson/flatpak
sudo apt-get update
sudo apt install --install-recommends flatpak
flatpak remote-add --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
flatpak remote-add --if-not-exists winepak https://dl.winepak.org/repo/winepak.flatpakrepo
flatpak install winepak com.blizzard.StarCraft2

You can also do the same following this guide for other distros.

Seat back relax, that's it. After it finishes:

flatpak run com.blizzard.StarCraft2

I was able to run the installer and load the battle.net login normally with a 64bit wine prefix, so I think it should work fine. This was done on Ubuntu 18.04, with wine-4.0-rc2. As a side note, I did have the multilib 32bit compat layers installed, but I don't know how much that affects 64bit wineprefixes.