It's not a lens cleaning panacea, but it's good at what it's good at 😉. Especially for travel, when you want something light and compact with you.
For dust, I use a blower. I tried brushes but found that they pick up oils from your skin if you ever touch the bristles, then transfer the oil to your lenses.
For water spots, I use ROR and lens tissue. Afterwards I fog the lens with my breath and wipe it again, to get rid of trace ROR residue. The Lens Pen has a hard time with water spots.
For fingerprints, the Lens Pen is superb and convenient. This is what I have to clean most often, so carrying a Lens Pen works well for me.