The EFF is on the right side of this one, if there was any doubt:

All too often, technology companies have raced against each other to build restrictive tangleware that suits Hollywood’s whims, selling out their users in the process. But open Web standards are an antidote to that dynamic, and it would be a terrible mistake for the Web community to leave the door open for Hollywood’s gangrenous anti-technology culture to infect W3C standards. It would undermine the very purposes for which HTML5 exists: to build an open-ecosystem alternatives to all the functionality that is missing in previous web standards, without the problems of device limitations, platform incompatibility, and non-transparency that were created by platforms like Flash. HTML5 was supposed to be better than Flash, and excluding DRM is exactly what would make it better.

Adding DRM to HTML5 would absolutely enable new web apps to be made, but guess what: The kind of apps it would enable are across-the-board worse apps than the apps that we already build without DRM. A vote for DRM is a vote for worse in every possible way.