I think that taking pleasure from default airplanes is just a matter of how you like your experience of flying. Some people don't take any pleasure in reading hundreds of pages of aircraft manual, nor or running checklists for a simple engine start. They rather just press ctrl-e for an auto start, and just fly. Nothing wrong with that, and I think in that case the default planes might be just enough. However, if you like to understand and control the aircraft systems in depth, and/or to understand and follow detailed procedures pre and post flight, the default aircraft just won't cut it. Especially the airliners. That doesn't mean the default planes can't be fun, it's just a different thing.