The phrase "pointless exercise" means doing something that has no purpose or benefit. It is an activity that is seen as a waste of time and effort. Full definition
This is a repetitive, pointless exercise in genre filmmaking — the kind of movie where you distract yourself by making a list of the sources. (rogerebert.com)
Second, trying to pin an appropriate P / E ratio on a volatile (and / or cyclical) business is a fairly pointless exercise. (wexboy.wordpress.com)