Bitpay is a way of converting crypto into dollars before then passing it onto the vendor. In theory that vendor is accepting the dollars and its Bitpay who handles the crypto itself, not exactly a crypto transaction. Hopefully they are also monitoring other methods of exchanging value not just ones that register in FIAT because that'd be quite ironic to skip transactions purely done in crypto
Bitpay was (is?) the largest payment processor for Bitcoin. They are seriously hurting Bitcoins usage as a means of payment though. They started mandating that BIP70 is used for payments. This put a bad taste in many peoples mouth and caused many users to stop using Bitpay altogether. I'm unsure why they mandated BIP70 for payments, but it just overcomplicated things. I am certain that this has to do with the drop in commerce, and is what skewed the results of this "study". Maybe it's also in part to the fact that Bitcoin has been in a slump since 2017. A lot of people are likely hodling because of the general perception that we will be entering another bull market shortly, and buying something would result in a net loss in the short term.
people have been complaining about it ever since they mandated BIP70 so there are posts on their blogs about it which you can read
https://blog.bitpay.com/bitpay-and-payment-protocol/ it may not make complete sense though. and i have heard once before that someone said it is done in order to make it near impossible for those using TOR to be able to use Bitpay! don't know how true this is though!
the article is based on Chainanalysis not the stat reports by the payment processors or merchants themselves so there is a good chance it is off the mark. it is also the fact that it is comparing bitcoin now (at the bottom) with bitcoin before (on the rise). people tend to spend their bitcoins when they have risen not when it is going to rise. it is the same as selling, you don't want to sell at the bottom, you sell on top.