recharge time and cast delay can be MODIFIED on a per wand basis
MEANING:
if you cast certain spells, those spells can change these numbers so just because a wand has certain stats doesnt mean it cant be "fixed" using spells. take heavy spread for example. if you find a way to include heavy spread in your payload, it will subtract 0.12s from the cast delay and 0.25s from the recharge time

so for example if we have a wand that has 0.5s recharge time and we use heavy spread to modify ANY one of the spells in the payload, the wand will now only take 0.25s to reload (0.5-0.25)
this is a huge difference, we're going from 2 shots per second to 4. now consider that you can trigger the same spell twice by "wrapping" around back to it, effectively giving you -0.5s recharge time, meaning after the wand fires all its spells it will be ready to fire again on the next frame
if you then also modify the cast delay down to 0, you have a wand that can fire on every single frame. the limiting factor at that point is how much mana you have to spend. sometimes its not great to make your wand go brrrrrrr right off the bat because the early wand stats just cant support that kind of mana usage