Well the claim is true to some extent but it is not necessary need for you to get clickfunnel before you can build one page website to capture contacts.
Clickfunnel is more of sales funnel rather than just capturing leads. if you want to build a landing page there are some such as you can make use of to do that. One of them is GetResponse. it has a lot of templates and you can also use this one to build a sales funnel.
Clickfunnel is a ready-made sales funnels which makes it easy to add up selling and I'm selling to every offer you want to create. It makes the whole process pretty much easier with just a point and click prebuilt software.