I laughed and deflected the question by saying you have to figure out exactly why you are writing. He took that, rightly, to mean "no."
But just a couple of days later I got my first check from Amazon for my Kindle sales. Thanks to my successful free promotion in February, paid sales had crossed the threshold where Amazon actually writes a check, after its self-imposed 60-day waiting period.
It was worth waiting for, because it was a relatively fat 4-digit check (hey, not counting the numbers behind the decimal point). Not enough to quit my day job, but enough to cover the actual costs of self-publishing with enough left over for coffee at Starbucks. Profit!
Many writers dream of being a zillionaire bestselling author. Most of us would love it if we could make enough to live the idyll of being a full-time writer -- you know, a couple hours grind in the morning and the rest of the day for revising, research and naps.
At whatever level, though, it's nice to make some money for your fiction. It's like somebody paid you for going to the ball game, enjoying a nice meal, or otherwise amusing yourself. It also validates your effort -- somebody thought it was worth it to shell out $4.99 to read your book.
One of the nice things about self-publishing is that a book doesn't have to go out of print. And the more titles an author accumulates the better the chance that all of the titles, including those first ones, will sell better. It's like planting a perennial in your garden -- it should keep blooming, year after year.