First, it was their development choice to use a wine wrapper for their port. It's not the same as running Steam in wine. This is the same as how Duke Nukem runs from DOSbox.
Second, many people prefer as pure a client as possible, not to mention its function as part of SteamOS.
You should contact the developers with your concerns. Closing as this isn't a Steam issue.
Nothing extracted yet.
Now wine "port" of game == native port? If now it approved, maybe need add icon for wine?
PS Why you make port steam for linux, if can just run steam in wine? :)
http://store.steampowered.com/app/252010/
From description:
"...Note for Mac/Linux
Mac and Linux version are Wine wrappers. They're not a port but in every machine we could test the game it ran perfectly and without any problem. However if you have a problem with these versions please e-mail us!
We can't get gamepad controls working in the wrappers, but you can use key mapping softwares (like joy2key). ..."