I'm a caffeine/coffee consumer because I like its effects, and the claims to overall physiological benefits appear solid, but why do you think multiple and varied spiritual schools choose to forgo it, especially in coffee form?
I don't think that, when all is considered, there are that many spiritual traditions that forbid it, and there seems to be no unifying principle from the ones that do. Mormons forbid "hot drinks" that are, for historical reasons, interpreted to include coffee. Salafists do it because certain early jurists briefly classified coffee as an intoxicant. Seventh-day Adventists avoid stimulants as part of a broader health code. Theravāda monks avoid anything that affects wakefulness after midday. A few Pentecostal or Anabaptist groups inherited older temperance rules about stimulants. These prohibitions all come from very different origins, and none of them amounts to a shared spiritual insight about coffee itself.
In fact, so few spiritual traditions do forbid it, including the most forbidding and censorious, that it may well be considered miraculous. In my personal religion it is tantamount to a sacrament ;)
