Yes, videos are one thing and games are another...However, HTML5 doesn't seem very well adapted to the sort of content lockdown that proprietary-content creators often want. Such lockdown is easy to achieve with Flash, however.
That goes not only for audio and video, but also for games and demos and the like.
For the latter, one can use HTML5 <canvas> or SVG controlled with JavaScript, but one would have to rewrite one's games and demos from the bottom up to use such approaches.
As Gruber so succintly put it: And as for Flash games, isnt it utterly obvious that existing Flash games, which work via keyboard and mouse, wouldnt work at all on devices which lack both keyboard and mouse?