I have a real hard time taking advice seriously from a company that doesn't have a career page on their own website. It feels like taking stock-market advice from somebody that only buys bonds.
"Careers" pages on websites are not particularly effective recruiting vectors.
That depends a significant amount on if you're interested in the "I want to work for company X" crowd.
You should probably have a "Careers" page on your website, because it doesn't cost anything, but it's not damning not to see one. We have a pretty good "Careers" page; we get very few inbounds from it.
I started a company in the recruiting space which we raised $1.6M for and I worked on for 2.5 years.