The idea behind numberals is that they’re associated with facts and that’s why we scan text for numerals.
As a rule do you always use ‘power’ words in headlines?
Writing headlines is part science and part art, so there are exceptions. Some headlines do well even if the benefit isn’t specific. Some headlines may do well even without a power word (having said that I can’t remember one).
By using a power word and making your headline specific for your own target audience, you massively increase your chances of attracting attention.
How about something that’s simple and direct, like “How I Cured My Anxiety?”
Anxiety is a power word because it’s emotional and you can almost feel a physical reaction when you read it. Anyone suffering from anxiety would be interested to learn how it can be cured.
Why some people make money writing and others never will
All headlines you’ve quoted are excellent, but this one is rather wishy-washy. Depending on the audience, these would be more powerful:
How Some People Make Shedloads of Money Writing
7 Easy Ways to Turbocharge Your Income as a Writer
7 Easy Ways to Triple Your Income as a Writer
How to Earn Your First $1000 as a Freelance Writer
Enchant readers. Woo customers. Win business.