The power of a filibuster is that it forces the opposition to experience pain, slowdown, and increased public scrutiny. It prevents bills from being passed quickly and silently. However, it's a risky move on the part of the filibustering senator, as continued use will cause the lawmaking process to grind to a halt and potentially cost you the next election. It's thus only wise to use it sparingly and when the public is clearly on your side.
This isn't necessarily true. The senate has a 'two-track' system that allows them to move on and address other issues where they have two bills on the floor at the same time.