Just wondering what was/is the reason to separately display "posts marked spam" in the flagging history. Could it be that "spam flags" carry different weight? Or I guess "spam" on SO is so rare that it calls for a separate count.
Spam and offensive flags have effects on the flagged user if enough of them accumulate.
A benefit of the separate counts on the summary page is so you know how often you're using them.
However, the information's not immensely valuable, I suppose; a valid flag is a valid flag, and how many you have shouldn't affect how often you do it, as long as you're flagging appropriately.