Burning of unsold token is definitely a good step to increasing the value of the project, cutting circulation is super solid plan and I look forward to seeing it work
This is always the case, reducing the available supply, is always a positive return for the project, it also has better trust by cutting the idle assets from the chain reassures customers that unsold tokens don't get used for other things down the line. Thats why theirs always a push for ICO's to confirm they will burn tokens before the exchange listings
In fact this process is pretty natural. Total supply of the project is the money people spent during ICO. If there are tokens that haven't been sold then these tokens cost nothing. So they must be burned not to dump the price of the remaining.