> What's the value of saying you were blocked but now you aren't?

Pattern detection. As a coder, your job is to get past blocks and deliver features at quality and on time. As a manager, your boss's job is to take information in from their directs, synthesize a picture of what's actually going on, and work to make your life easier (and thus, you more productive) in the future. "I was blocked for four hours yesterday because <x>" isn't a big deal, for you; but seeing the commonalities in <x> across the whole team, and over a longer period of time, motivates action to understand the /underlying/ problem and improve it in the future.