Please stick to a font already in my browser. My network is slow and webpages sometimes get stuck loading; the resources in your page took 40 seconds to load and your font didn't even load yet.
Testing a big more, just dropping "dlig" from the feature settings declaration turns off the awful st ligature. So they don't have to 'all' be turned off to get rid of that one. What I don't know is what other ones get turned off by dropping "dlig" from the declaration.
In the modern age Latin script, the only acceptable ligature is "fi" in a proportional type, because the top curve of the F usually comes very close to the dot of the I already. For the rest, they're totally useless because we don't use moveable type anymore.
Well, I also tend to enjoy programming ligatures, such as != becoming ≠ or => becoming ⇒. (but in a size proportional to the pair of fixed width characters, see https://github.com/tonsky/FiraCode )
But then I don't inflict them on anyone but myself and people who look over my shoulder...
That is why I disable custom fonts. Everything on the web is one of two fonts for me, sizes 9-14. I've been doing it for a decade and it makes websites so much better.