For teas, the only thing I can tell for sure is that when I drink chamomile, I just fall asleep. For others, I am not the best person to tell because I drink tea rarely.

Tinctures, I started making them just a few years back, so I'm a quite new, but I do use them all the time. So, tinctures can be used to eliminate a symptom (ex. take X tincture to break a fever). You can take tinctures to prevent stuff / balance your system, for me this is extremely important (ex. X tincture in lower dosage boosts immune system, so you take it during winter not to get a cold). If tincture X doesn't work for you, maybe Y would or Z, so in a way the more you use them, the more you know about what works for you.

And lets remember that the base of pharmaceutical medicines come from all the collected knowledge of the effects of plants for millenia. Consequently, there is a tone of scientific research on plants and herbal therapy. For example, here are several scientific articles about herbal therapy and multiple sclerosis. In the same time the scientific research is not enough because pharmaceutical companies prefer creating elements in the lab instead of harvesting them from plants.

Personally, I use both western medicine and herbalism. I don't trust herbalists who tell you not to go to the doctor and stuff like that. I don't trust doctors blindly neither, because scientists can disagree on diagnoses, cures, approaches, etc. Appart from genuine disagreements, some love too much what the pharmaceuticals offer them. Herbalists have very different opinions, so if I dare say so, you have to formulate your own and allow it to evolve with time. There are a lot of amazing resources online for that. I use some resources relevant to where I live, and for more general info I like this site a lot: https://www.herbalreality.com/.