I can confirm your intuition: this is certainly not the most common kind of concept encoded by ideophones. It is somewhat of an outlier in the dictionary too, but such a nice one that I couldn’t resist posting it.
And yes, it’s considered an ideophone (Japanese linguists say gitaigo or mimetic) because of its reduplication and its morphosyntactic patterning.

Not having worked with heavily ideophonic languages, I’m really impressed by this example. From my naive and uninformed perspective ‘Waza waza’ doesn’t seem like the kind of concept that would normally get expressed by ideophony — but is it really as unusual as it seems to me? My real question, though, is how this element is identified as an ideophone. Is it because it patterns morphosyntactically with elements that are obviously ideophonic?