Anything within reach of your tub. Wash your pets, rinse cloth diapers, clean the shower, rinse your hair. The sprayer connects to your standard toilet water line before it reaches the toilet, so daily use is pretty open ended.
One thing it's not designed for: internal use. The sprayer isn't built to control the pressure, temperature, or sterility that an enema or douche requires, so stick to external cleaning only. When in doubt, talk to your doctor.