I think the biggest issue with npm these days is the same as Node.js in general... you wind up in a weird effort to mix/use ESM and CJS packages, which winds up being a bit of a convoluted mess. Where Deno/jsr is based in TS/JS source trees with ESM patterns as the primarily supported method, with npm/cjs as a compatibility shim.

Http (with and without import-maps) supports direct links to github as well.