If you write it in the policy "To make a claim, you must upload a 1 minute video via our app or website, together with photos of all receipts you want us to reimburse", then you are totally within your rights to deny all claims where the customer can't/won't follow your process.
If your insurance company existed in a place without laws and insurance regulators, that is a methodology you could impose on people in order for them to receive what they’ve already paid for. And good on you for ignoring the part about what to do about all those pesky customer questions, particularly the ones that come after a disaster you’re on the hook for.
The whole “why haven’t they considered that they could be more efficient ?” train of thought is tiresome. Admit that it’s a business you know literally nothing about and move on.
