They are a lot of work to put in but are used a lot in arid climates, in Australia they are called wicking beds. I use the principle in all my windowboxes as I keep forgetting to water them. Also used the double bucket with success for tomatoes on the patio.
Basically you create a water reservoir and fill that up directly instead of watering on top. Then you need a “wick” to help the water go into the soil above, I used earth-filled pots suspended into the reservoir. Lastly, some sort of overflow.
Because of my forgetfulness I made a wicking base for all my starts that I plant out later, using sand instead of soil, and nestling the pots into that.