Ask HN: Why would I use Openrouter over something like DeepInfra directly?

As far as I understand it, OpenRouter is just routing to providers such as DeepInfra (and others) who already provide access to many open-weight models. If my goal is to just use open-weight models and maybe add an extra key for OpenAI or Anthropic when necessary, what's the point of the 5 percent markup?