[mikets]

Well, the .*project files contains the Wind River build environment preferences. If you don't check them in, every programmer in your team has to recreate the build environment. For example, we hit a limitation last year with our code that it got big and exceeding the "short call" distance. So I had to add -mlongcall to the build option. That modified .wrproject. If I didn't check it in, all the other programmers had to do the same to their build option. If I check them in, all they have to do is to sync the files.
The .*project files are like makefile. They are part of the project. If they are not checked in, it will be more steps for each programmers to add/remove/rename a file to the project.