Depending on how your dehumidifier works you can use it for many things.

If it’s chemically operated the water is going to be full of whatever hygroscopic salt is being consumed so maybe just for washing clothes/dishes

If it’s the standard refridgeration based type then it is essentially collecting distilled water from the air. However that water is then left to stand on the cooling surface/in the resovfrenchnoiseswhocanspelltheirwords.

It might have collected some dust, mold, or algae. It could have also trapped any contaminatants from the air in your home as air was cycled past the wet elements.

I would not drink or cook with it, but unless you are operating it next to a source of harmful pollutants like say a 3d printer, stove, fireplace, or a very moldy laundry it is going to be fine for washing and watering.