I can't imagine that Bitpay is going to leave that there any longer though, it seems like a mistake for them to do so and now that it is publicly known, it will probably go away.
I actually thought the exact same as you, in putting this out as pub. as i can, bitpay will now remove it (which will hurt me bc i always use tails liveOS for ANY btc wallet access).. BUT it looks like this was the right move! (and right move by bitpay, for once). the post here and at reddit, got a reply from one of their reps (on reddit, of course , but they published this KB (so looks like the -noscript url trick will stay!! ):
https://support.bitpay.com/hc/en-us/articles/115003014566-Why-can-t-I-pay-a-BitPay-invoice-in-my-Tor-browser-