bitcoinvisuals is a nice website, thanks for sharing.
Sadly they do not have their own API, the data is available only in CSV.
You are welcome, bitmover. It is not for real-time data analysis but at least with their CSV dumps, you can use such data set and merge with other available datasets that you have, then play with the merged data.
From June to December 2019 the price was in strong downtrend. I believe there is a considerable number users who just sell their btc during that time. So they get btc out of their lightning channels.
You can see a clear correlation with the price in both chartst (BTC locked and USD locked)
It seems to be right but that price fall is not as bad as dump in late of 2018. In 2018 (late months), total lightning channels look stable and even increased very quickly after that fall. People probably were more panic in late 2019 or some other things happened.