I can't get Steam to run reliably at all, it crashes on login, and the last time it took Skype with it! And those instructions make less sense than anything I've seen. "How to install Terraria on Steam. Step 1: Install Steam. Step 2: Install Terraria. Step 3: Wait why am I writing this? Didn't you just do it?" Not that the instructions were any more detailed. "Install Steam" is one of the least useful instruction steps I've seen - especially when that's the HUGE issue that no one can really handle!
Actually I had no problems with installing Steam directly from the site through wine - After I made sure to upgrade my wine to the newest version and got winetricks configured. I was using the previous version of wine, and apparently quality steam compatability is very new. I've had no stability issues since upgrade - which version are you using? I have gotten a lot of the "winetricks" modules installed though, to get previous programs to run, so if you haven't used that it may be worth it.
Installing steam for me involved going to the steam site, downloading the installer, and then running the .msi with wine. And that worked flawlessly (after upgrading to the new version of wine, it failed first).
Note also that there is a link to a different set of instructions at the top of that post that you may have more luck with.
I'm not saying its easy just yet, but it appears possible to get it to work, and that seems to be a relatively new change.