Loading time is a major contributing factor to web page abandonment. The average user has no patience for a page that takes too long to load and justifiably so. Slower page response time results in an increase in page.

Yes. You are right. You can loos your visitors and potential clients if your page loads slow. That's why Google has included it in it's ranking factor.

It is one the most important factor that can affect your business. So if the page load speed is very low then most of the visitors will drop off and you won't get the output you want to have.