Sounds still interesting, if only to achieve the opposite effect: Make moisture rain out over the ocean before it hits the land and causes rain there. There are plenty of places that want to avoid rain at certain times, and having a laser installation would probably be much more convenient than having to fly over to drop chemicals all the time.
As for dry areas: 70% instead of 100 could be a big improvement. If you are in a desert and the RH is only 20% by daytime, this could increase to 80% at night solely due to a 20 degree (centrigrade) temperature drop. This could happen every single day without ever producing a drop of rain unless you interfere with the system.
Digging wells isnt practical everywhere, and pipelines would be problematic for landlocked countries as you need to get the water from somewhere. Rich dry countries with a coastline just proceed to build desalination plants, which are fairly cheap as long as you have a cheap source of energy.