Interesting data. This[1] seems to suggest that this relatively small solar sail would be able to reach the moon from earth's orbit after ~3 years (I could be horribly misinterpreting this data!). That seems impressive, given how "simple" this method is.
However, it strikes me as difficult to use this the deeper into space we go. I would assume the further from the sun you go, the less thrust you receive from the sail. Also, how do you slow down and stop? Maybe you don't...
Sure, the amount of acceleration you get decreases as you get further from the nearest star, but that’s ok. Remember that you keep all the velocity you gained along the way, when you’re in space. You can be going pretty fast by the time you turn your sail to face the star at your destination.
However, it strikes me as difficult to use this the deeper into space we go. I would assume the further from the sun you go, the less thrust you receive from the sail. Also, how do you slow down and stop? Maybe you don't...
[1] https://spacemath.gsfc.nasa.gov/weekly/5Page26.pdf