It's possible that an ideographic writing system is faster to read, presuming one has got over the 'learning thousands of characters' hump without it affecting your ability to comprehend, as you're not converting a representation of sounds into morphemes, and ultimately words, into something meaningful. That is, the characters (or small clusters thereof) are meaningful in their own right, somewhat. That more direct mapping to meaning -- albeit somewhat abstracted over time -- might also be advantageous in terms of learning simple nouns and constructs (e.g., "this character means 'horse' because it kinda looks like one", etc.).

One would have to test the comprehension and reading scores of kids from alphabetic and ideographic backgrounds, at the same ages, to see if that argument held any weight.

I would be interested to know if the effort taken in memorising thousands of symbols has a beneficial effect on brain physiology. It's obviously much more computationally taxing than an alphabetic system: would this lead to better overall working memory ability, or would that be offset by the extra energy it takes to process?