So, with a MAF setup the classic knowledge is you have all this metered air, that is now gone. The ECU doesn’t know that air is gone so you’ll end running rich, throwing off your AFR’s.
I run a BPV on my stock setup. Note there’s many BOV’s that can be plumbed to recirculate essentially activing as a bypass valve, if you use a bov as recirculating or use a bpv, you should just plumb that air back in after the MAF.
My take is that this doesn’t matter that much for fueling, but the work was already performed to compress that air, so if you care about spool, put the air back. Rally cars recirculate to help keep the spool going.