Well, CBD isn’t exactly “good for you”. Like, if you’re in perfect health, it won’t make you healthier. It’s not a vitamin or anything. It’s not like all these drinks that add açai, or ginseng, or some other “superfood” additive. CBD is medicine. It’d be more akin to adding some Tylenol to your drink.
I also wouldn’t say that CBD relaxes you. I take CBD oil twice a day, it helps my gastrointestinal symptoms and muscle pain, it does nothing for my anxiety or insomnia. I use a high THC indica for sleep or if I need to relax.