I can't find the post at the moment, but I recall Joel saying that they moved to dotNET, so that they could use the C# language, rather than C++ (as used for Eraser 5); it was thought that C# was the easier language and would encourage more people to participate in the open source project. Sadly, this did not happen.
Given the number of applications that now use dotNET, it can be quite hard to avoid installing it on a machine these days. Bloatware or no (one person's bloatware is another's fully featured app), you only need to install it the once. Of course, like most any part of the Windows ecosystem, it makes its own contribution to DLL hell.
I can think of reasons why I might not want to use Eraser in its present form. But its use of dotNET is not one of them.