I was assuming that falling back to low-bandwidth or even non-compact block relay would be better in the case of a very large prefilled transaction (or even a large prefilled coinbase transaction). If we have three HB peers that send us a compact block with a very large transaction prefilled, we have 3x the download bandwidth usage, and are likely hitting the TCP window size? While non-high bandwidth block relay might still be a bit slower, ideally we wouldn’t download the same prefilled data 3x? I think this is a speed/bandwidth trade-off.