I've been a plastic kit builder for close to 40 years. Can still recall the mess I made building an Airfix Folland Gnat fighter when I was 6 years old. Card modelling used to be limited to pre-cut HO scale buildings for wargame/dioramas. Then in about 2004 I was on a 6 month sabbatical from work doing paid research (followed by 2 months sick leave). During that time, being frequently bored, I was doing a LOT of internet browsing and gaming. Looking up some details on Homeworld, I found the Paperstarships site and Gearz Taiidan frigates. Before long I was hooked and was building as many Homeworld models as I could download I can't believe that these are 4 years old!!! From there I was saving every file and pattern I could find (never ever get round to building them all I guess, but I can dream I suppose...) Anyway, as previously stated, there is a huge range of models most unavailable in any other format, relatively low cost, limited mess (sanding painting etc) although I do use loads of varnish coats on the finished model to protect the finish. Flexibility is an issue as well. To be able to resize most models as you like.