Basically you're betting on volume and speed over maximizing the value of each individual block. The logic is that if you're a big enough player those fractions of a second you save by not waiting for the mempool to fill
No, mining doesn't work like that; no pool waits for their mempool to fill up. While this is off-topic, here is how it works.
Type 1 pools:
They start mining before downloading and verifying the block (just the block header is enough); they save a little bit of time (a few milliseconds or maybe a whole second!) and these are subject to mining empty blocks not because their mempool is empty, but because they do not know which transactions were included in the last block, if they happen to include any of the already included transactions in their newly mined block, the block will be rejected by the entire network since it contains an output that has already been spent.
Type 2 pools:
They download the entire block, get all the transactions in it, remove them from their mempool and start mining the new block. These pools will never mine an empty block unless their mempool is actually empty (extremely unlikely to be the case).
All of the above is unrelated to this topic, by the way. you could read my previous reply for more info.