My reason to dose dry is based off 1) experience and 2) less mess of a liquid dribbling, spilling the liquids, leaking caps etc, also, it's yet another conversion I need to make and figure for each tank volume based on the mls of the solution.
It's more complicated basically.
You do get more accuracy, but the accuracy is not needed so I do not bother. I could spend 300$ for a scale to weight things out precisely for both dry and liquid ferts, but ............we do not need the accuracy(the cheaper scales do the job to 10mg ranges fairly well), so why bother in the first place?
Many folks do not want to get a SCALE IN THE FIRST PLACE FOR 20-30$.
That seems to be a good enough reason alone not to bother.