I´ve been using Steam for several years and I´m surprised at some of the reactions in the topic. There are some distinct advantages to using Steam as a consumer. First off, you can purchase and download all your games in one place. Steam keeps track of what you´ve bought, so no more losing codes or download links or whatever. Secondly, Steam keeps your game up to date, meaning as soon as the developer releases an update/patch, Steam applies it to your game and you're good to go. If FeelThere does it right, they will also make Steam Workshop available for the game. This allows developers and players to create add-ons (e.g. new a/c, liveries, airfields) and other players can add them to their game simply but selecting them in steam. No more fiddling around with seperate downloads and moving files around. Also, Steam Cloud allows you to save your games in Steam, meaning you can install the game on muliple machines and share save games or profile settings (or add-ons...) across machines (no need to move your manual Airfield updates from pc to pc). From a multiplayer point-of-view, Steam has a "Friends List" so you can add players as your friends and Steam will tell you when they're online and what game they're playing.
I'm not convinced that Steam is a memory hog. I think on current hardware, you won't notice Steam running in the background. I think we also need to clear up how Steam works. Steam is no more than an "Administrative" layer for your games. Your games don't run IN, ON, UNDER or OVER Steam. In-fact, when you hit the "Install" button in Steam, it downloads and installs the game on your harddrive just like you would normally. When you play a game, Steam retires to the background so that the games has priority. You could even uninstall Steam, and all your games would still be there. I have a laptop from 2009 and it runs Steam (and several games) fine. This isn´t like the old days when people preferred running games under DOS compared to Windows 95 because "Win95 is such a memory hog".
Steam also has advantages for FeelThere. I think the most important one is that they will get exposure to a player base unlike anything they've seen before. In Febuary 2015, Steam counted 125 million(!) active users. I think a LOT of those people may enjoy a game like Tower, but just never went looking for it. The only reason I found this game was because Global ATC Simulator went live on Steam and I was looking for something better (and stumbled on Tower!2011). I'm sorry to say that folks claiming they will not buy the next Tower release if it's on Steam only, are being very short-sighted. If Tower!20xx is more of the same, but with 3D... are you really not going to buy it because it's only on Steam? Do you really think that FeelThere will regret loosing maybe 100 players if in return they get exposure to 125 million?
Personally, I think platforms like Steam are the future of gaming and FeelThere need to take full advantage of it, but only if they fully integrate the game (so with all the added benefits like Workshop, Cloud, etc). Simply using Steam as another distrubtion channel is not enough. In-fact, releasing a game via Steam and then telling people to get their updates from some other site is going to hurt you more than not releasing on Steam. On the other hand, you don't have to do it all at once. There are plenty of games that have released as stand-alone games and then later moved (or added) to Steam. Microsoft Flight Simulator X is an example....
Just my 5 cents, but as a long-time Steam user I felt I needed to respond to this thread.