I agree with the idea that we're mostly automating manual work. The really nice thing about automated tests is that they can also go much further than I would

I agree with the idea that we're mostly automating manual work. The really nice thing about automated tests is that they can also go much further than I would ever bother to manually. For example, I might manually check that a couple of product pages are showing, with an image, price and description. With automated testing I can check all product pages, every time. It can also test a tedious amount of interactions, e.g. various interleavings of "add to cart", "remove from cart", "checkout", "press back button", etc. Manual testing still gives me confidence that automated tests can't, e.g. that an "unknown unknown" hasn't taken things down. Yet that's all I need to check manually; if pages are loading and look right, I don't feel a need to manually check all of the ecommerce arithmetic, permission logic, etc.