I've worked with enough tech companies and startups to know that projects these days have to move fast and be ready to change course on a dime. While PMI (Project Management Institute) style planning is a good fit for many industries, the question "Why bother creating and estimating project tasks?" is firmly targeted at those of you who work and thrive in highly changing environments. Why not just plow through the project?
Really? Might there be people (like perhaps your stakeholders) who want to know when your project will be done? Does anyone care if you're on track or not? Are there competing priorities? Is there a deadline? If the answers to these questions are "no," then kill the project. Otherwise, invest a little time to identify, estimate and manage your project tasks at the outset.
Expect your first swag at tasks to be a bit fuzzy at first. You can get clarity by digging into what the tasks are and how long they might take. It's not realistic for anyone to think that you're going to be perfectly accurate. Like anything, you will refine the project as the team delves into the work.