A year ago, I would have agreed with you. There's nothing stopping you from building a successful product without writing tests. Since I built the habit of writing tests, though, It definitely makes a difference, especially if you're working with a team or contractors.
Tests are a super helpful way to say "See, this works. Make sure it keeps working, everyone."
Tests are a super helpful way to say "See, this works. Make sure it keeps working, everyone."