As an ex flash designer, the problem is often that doing these kind of stunts in HTML5 takes way to much time for an average result at best. And the browser tends to behave in unexpected ways( horrible lags when scrolling in Firefox, timing will always be an issue when it comes to webtechs and animation,especially with CSS animations that are totally unreliable , Flash kind of guaranteed a stable frame rate at the price of a higher memory and cpu cost ).

People are also less patient today, they want to get what something is about in less than 10 seconds when they visit a new website.

This tool seems targetted specifically at designers and front end devs, a distinctly visual group with a high level of overlap with the "appreciates cool front end techniques" group. Maybe in this case it's actually a canny strategy for getting their attention?

If this was a tool for capturing and analysing network packets in vim, probably not as appropriate...

I also noted that the site loaded and animated poorly in FF, but was much smoother in Chrome. I thought it was a much nicer experience when I switched browsers. Does that say anything about this tool? Possibly!