Heh, I did this from the get go when I started doing my own (simple hobbyist break-out and carrier board) PCBs, adding thick ground traces until all nets passed DRC,
then adding ground fills where useful. I blame my suspicious nature, and the wish to spend a little extra effort to ensure things work the way I want. (I also like to add more than the minimum spacing between tracks and tracks and pads.)
The downside is that when using spoked connections to pads, I often have to remove at least a final segment from the trace to avoid the extra-thick spoke or full connection to the pad. Not much of a downside, but when I forget, the pad spokes can look wonky. (Somebody commented about one in some thread here.)
I never thought that it might actually be the more reasonable way to do it.
Edited to add later on: The results from effective current loops wrt. susceptibility to EM interference and related antenna effects was something I hadn't thought of before, though. Good points!