A) this increases ripple voltage which eventually impacts RX noise floor. As long as you have enough headroom at the input to your regulator power saving is great, but eventually having a more consistent load becomes the limiting factor for many devices.
B) drastically increases typical latency - not an issue for all applications, but the ESP-IDF network stack has a Nagler that can't always cleanly be disabled and tends to write each little bit of the next layer to the TCP socket.