You've misinterpreted that part of the article.

The reason to avoid a monetary reward is not that it is tacky, but because money can easily be used to pass on influence to offspring, such as by boosting their profile, or buying votes for them. This can undermine a selection mechanism where they should win or gain reputation by engaging in pro-social activities.

Also, not everything may be monetised. I cannot sublet the garage attached to my apartment for example, because the contract forbids it. AirBnB is banned in some cities/situations.