I can't go against steemit because steemit is a big platform and lot of people are earning on it by writing the blog on steemit.I believe that it works properly and paying a revenue after 7 days.
It helps the newbies to motivate by showing their post on the top and the new one get motivated.It is time needed for steemit to collect the revenue for the post and so for that 7 days is proper.
The genuine posts are always comes at top at hot section and for that steemit community gives payment in terms of steem after 7 days because if steemit started giving payment on same day then how can they identify the mistake and many more problems should have to face by steemit,so 7 days payout is working properly for everyone and no one have problem of this.