Inkscape is terrible for making diagrams. It's more for art and icons and so on.
> one of the best snapping systems ever created
Not the best though. That honour goes to IPE.
IPE is also a pretty good diagram editor, though it is quite heavily tied to LaTeX and more oriented towards maths / geometry diagrams than technical block diagrams. Draw.io is best for the latter, except for the stupid limitation that you can't really export text objects to real SVG as mentioned in the article. It just embeds HTML objects in the SVG which means they only work in browsers.