Hi Engggu,
You never want to run piping in such a way that the only consideration is to make it look good. Ideally, a pipe chase is available where you can run your piping and service it if ever a problem arises. However, not every job is ideal and you have to run your pipe in areas where it is exposed. Consideration for aesthetics is possible only after consideration for servicing and maintenance. Sal Sham made some good points and those points should be kept in mind before enclosing your pipe and making it inaccessible.