The general rule of thumb is that Browser-based games are strongly preferred as it greatly reduces the chance for someone playing the game to have their PC compromised with Malware/etc.
Someone trusted in our community needs to vouche for any executable so other members know that the game is safe/etc.
That's the unfortunate reality when a Platform has low curation on uploaded content, and why we have a strong preference for Browser-based games.
Viewing post in Only browser games are allowed and no exceptions?
Not our Jams specifically (thankfully), but it has happened in other popular Jams.
This measure is mostly a preventative one.
Try to imagine being in my shoes where some hacker could ask the same questions you are and then post a malicious executable and have a bunch of peeps get Malware/Ransomware and greatly inconvenient peeps.
There would be less trust in our Jams and therefore less turnout.
All it takes is one unfortunate incident to remove trust.