Plotly's built-in lasso selection is non-trivial to achieve in Vega-Altair.

Plotly offers more built-in chart types and supports some more exotic coordinate systems than Vega-Altair out of the box.

Since both libraries use D3 and SVG under the hood, charts can easily be converted from one library to the other.

Linking charts that use a common data attribute is more straightforward in Vega-Altair.