Actually the holes in the bottom are a neccesary item.
without the drain holes the water cannot drain from soil causing many problems like the roots to suffocate, which eventually leads to root rot and death. Suffocating roots cannot absorb oxygen and nutrients from the soil. Waterlogged conditions in containers of soil also favor the growth of mildews and other fungus problems.
Without drainage, excess moisture can't escape the pot so it becomes trapped in the soil. Even if the top of the soil feels dry in an pot without drainage holes, moisture trapped in the bottom of the pot can still cause rot issues.
In fact even in pots that have a single drain hole, depending on the type of soil can suffer from suspention. That is the area in the bottom of the pot that gravity cant pull the water from because the friction between the soil, and water is more.
In a container that has no holes your plants will have 2 situations, either they will be underwatered because it is impossible to consistancy water a single area due to the soil absorption disruptions below the soil line, or they continuously loose root area in the container as they cannot survive in any area that is undrained, due to the contaninants from the soil rotting in a oxygen deficient environment.
If you dont want to have the holes in containers it would be much more to your advantage to just go hydroponics, the pumps keep the water oxygen rich, you can keep it nutrient rich. the plants will grow water roots instead of soil roots(not nearly as strong, but will survive)
The greatest problem with growing plants in holeless containers is that, they dont grow with both water roots, and soil roots. If started in water and left in water, they will survive. If started in soil and the area under them is saturated to the 1" line, nothing will grow below it, in fact nature will tell it to stall out just above there, because it is all the water it needs at that height because of absorption. And the plant will start growing more roots at the level above the water. now 2 more times of water, the water comes up to the 2" line, the roots that were there start turning to water roots. The area about 3" from the bottom now explodes into a fury of root building action because the ones now underwater are not working 100%, but the top is still growing.
soon the bottom 4 inches are not really usable to its compasity,