Being a Clickbank vendor?

The real question is about "Being a vendor", not "Being a ClickBank vendor".

How much you earn from your product depends on a whole list of different factors, such as the quality of the product, the demand for it, how professionally written its sales page is, how you go about selling it, how you find affiliates for it, and so on. "Whether you use ClickBank to sell it" is barely relevant at all. By comparison with all the important stuff, where you sell it isn't really a factor that determines your income.

If you list your product for sale with ClickBank, the sales page will still be on your own site, and how much you earn will still depend on how good you are at finding and converting customers (and affiliates).

It's true that you may find one or two affiliates just by listing it at ClickBank. But it's far from certain, and if you don't have all those other things professionally attended to, presented and dealt with in the first place, they won't stay with you anyway.

The big potential attractions of ClickBank include ...

(i) There are many affiliates there
(ii) Affiliates trust ClickBank's system because if we use that, we're not dependent on the vendor for payment, and not dependent on PayPal either (for pro-affiliates - i.e. the ones you really want?! - this can be a huge factor)
(iii) You effectively get the bookkeeping done for you, by ClickBank
(iv) Customers can pay by PayPal without the vendor needing to use his own PayPal account to collect that money from ClickBank (also potentially very significant)
(v) It's very long established and has a reputation for prompt and reliable payments

Some of those factors also apply to some other affiliate networks, it's true.

Take time to check these threads:

Clickbank / Selling Digital Products

1. You CAN make money with Clickbank
2. OMG! My FIRST Clickbank+Amazon Earnings! Please tell me that I'm not dreaming!
3. how to sell 1000 copies of an ebook
4. Promoting Clickbank Product