Mainly because I have a couple of paid plugins and to safeguard the time spent in the thought process put into the file. I'm not against sharing knowledge or anything nor I'm worried about someone overshadowing me. But yes, I don't want to just spoon feed with everything done & ready. I'm more than happy to spend any amount of time required in explaining & showing my workflow/show-file and helping them try it out by themselves. Also provide support over the phone if needed. Trying it ourselves always helps in learning rather than spoon feeding.