When did estimates turn into deadlines?

Working in smaller steps is how you should build software. Constantly get feedback and re-evaluate what you're working on with other members of the team. Instead of giving an estimate, use t-shirt size.

With constant feedback, the whole team is participating in the emergent complexity, instead of being passive and just annoying you with "is it done yet"?

but what if I’m working on something meaningful?

I can’t MVP my way to a simulation physics engine, when each feature or partial feature requires weeks of planning, testing, iterating and tweaking- privately, before anything can be delivered to be used.

Feedback, implies a working widget.