air conditioner venting pipe functionality
No, it is not better to pump the hot air into your house. The vent is outside for a reason and by-code because it will also expel condensate (ie water vapor condenses out of the air when the pump compresses air.)

If you are worried at all about 'energy leaks' then ensure the drain pipe has an escutcheon and it seals tightly to the exterior wall so that drafts/cooling loss don't run up your power bill.  You can use a paintable, water-tight, exterior caulk to seal the escutcheon to the wall, if necessary.