Demo hasn't to be better than actual. It is possible in bucket shops, yes.
But here demo accounts for following items:
1. To show the pricipals of ECN trading (client's fitting, etc..)
2. To show the use of external liquidity (not like most businesses use autoconfirm). And usually demo at LP's worse than actual (the reason is quite simple -- real and demo money)
3. To test a few changes in ECN engine before installation them actual.