Nobody needs a pitch deck for your hobby. If it lights you up, the explanation can stay short.

Something that is genuinely yours does not require a case to be made for it. The pressure to justify a hobby comes from treating everything as an investment that must produce something, and under that rule anything done purely because you like it looks indefensible. Enjoyment is a sufficient reason on its own.

When someone asks why you do it, try answering in one short sentence and stopping there. Notice the urge to add a justification about health or skill or the future. Let the pause sit. Most people accept the short answer far more easily than you expect.