Freemium isn’t the only option to allow people try the app before buying it. There are free trials that allows to use the app for several days and then asking to pay the full price to continue using it.
A time limited trial seems like the perfect fit for productivity apps, not sure entertainment based apps would want this model. You have a day/week/month to use the app in its entirety, if after the trial you value the product you purchase it, otherwise it no longer works.