TTW has shown BLs to be faster than RoLs
in unupped, BLs do 3 damage, and photons can stay around for more than 3 turns
in upped, BLs do 5, and RoL needs 5 turns to do the same damage, considering a lot of TTW is 4, or even 3, RoLs are slower
AND if you ever need something to cremate, minor phoenixes are good, unupped phoenixes do 7 damage a turn, to cremate that would slow you down, so photons are used, in upped, BLs do more damage than minor phoenix, and u can always revive the phoenix
which is why we use BL