Q: Can I drink it?
A1: Not if you want to be healthy. Condensate water is definitely full of bacteria, dust, pollen, and fungi. Besides, the inside of the tank is gross.
A2: Not unless you weirdly like to drink distilled water. The condensate lacks dissolved minerals to buffer and add flavor, is relatively acid, and tastes nasty.
A3: Not wise because, depending on what the chiller or air handler is made of, the acidity of the condensate will dissolve copper, aluminum, and possibly lead and zinc from solder joints and tubes. If you want trace metal supplements, take vitamins without the lead.
Q: Can I water my plants with condensate discharge water?
A1: Probably fine for houseplants, flowers, or perennials. I'd be especially hesitant to use for leafy vegetables, considering A3 (see first question).
A2: About half of all Americans get drinking water from groundwater well sources. Many of these people have excessively hard or iron or sulfer fouled water and use ion exchange technology to convert natural calcium salts to sodium salts that have a lowered tendency to congeal soap, or more "softness" as they say. Some water is naturally saline as well as hard. A sure sign of hard and/or saline water is that white crust that builds up on the soil surface or around the base of a house plant pot. Eventually, the increased soil salinity from adding highly softened water starts to rob the plant itself of water through a process called "osmosis". Using condensate discharge to water plants helps mitigate against this problem.
A3 Watering your perennial garden with highly softened water slowly builds up salinity until the next strong rain comes along. Doing this over a long droughty period ads stress. If you have condensate water at hand, it would be better to water the flowers with it than with saline tap water.
A4: Take a look at where your air conditioner condensate discharge line spills out on the ground next to your residence. Generally its close by the compressor. See if the surrounding plants and grass are vigorous. Are they fine? OK.