wish i had one on all my bikes... have one on the rando / light touring rig, have one on the adventure / touring / bikepacking bike.
i had one on the bakfiets. wish i had one on the yuba mundo.

a shimano hub can be had for >~$100.
lights are pretty reasonable, to get something serviceable front and rear.
charging components can be had separately, or as part of a light (Luxus U, and a couple of others).
for me, they allow you to ride whenever you want, not worrying about lights... or power, if setup properly.
especially if you tour off the beaten path, away from a cafe or hotel or campground a day.


battery packs do OK too, so thats a good option. really depends on what you want out of it, and how tied to mains you want to be.