In my experience most case do come with fans, although the fans supplied are often not much if any good.Most cases do not come with fans it gives the builder a choice of fans they want to use. I have an Ophion MITX case, it didnt come with any fans, I Opted for 2 120mm Exhaust fans and a 120mm inlet.
Using both intake and exhaust ase fans is similar to using push/pull fans on coolers or radiators. Fans with good pressure ratings are only good for about 2c at most lower temps and increase noise level to same level as single fan spinning a little faster and giving same temps .. end result is we have the same temps at same noise levels with maybe a couple degrees lower temp at a few dB louder noise level at full speed.