Presumably to disable that hot linking from other websites/apps. Especially if they use scrapers.
But yeah, bad ux.
Obfuscating the image file like that is usually completely transparent to scrapers actually, as the image URL is almost always in the HTML. You can find the direct image link yourself if you poke around in the element inspector for a bit.
It’s just to make it harder to copy and increase to amount of people that link the full site URL (with the tracking and analytics ofc) instead of the image directly.