After the crowdsale, you can still buy the tokens.
Current price 26th Dec:
$0.0005 ($1 for 2,000 DOOH Tokens)
28x cheaper than buying advertising in fiat
December 27th 2018
$0.0010 ($1 for 1,000 DOOH Tokens)
14x cheaper than buying advertising in fiat
As there will be user who will still want to buy the tokens for advertising usages.
People will be able to buy tokens on exchanges after crowdsale. And selling tokens (even with higher price) after ICO is not honest. You just must burn unsold tokens and develop product...
These are there as opportunities for those looking to advertise, as the rest are placed in a reserved pool.