Seaborn isn't usable without matplotlib, nor does it aim to be. It gives you simple high-level calls and as soon as you need to tweak your plot you're back to matplotlib. (Similar to the pandas plotting shown in the article actually.)

Bokeh is nice. And has made huge improvements over the past year or two. But it still doesn't directly compete with matplotlib because it's more focused on interactive plots.

Bokeh and Plotly obviously do much, much more than matplotlib, and if you want what they provide, you would go for those. Seaborn is more presentable-looking by default and easier to get things laid out in. I personally haven't used straight-up matplotlib for a long time.

Bokeh and Seaborn are very, very thin skins over matplotlib, and honestly don't improve the user experience at all. Only Altair has changed things for me.

Bokehs rendering backend is bokehJS

https://bokeh.pydata.org/en/latest/docs/dev_guide/setup.html

Bokeh is not a skin over matplotlib.