The Is CTA Iink option is used to specify all links that are the main CTA on the page, which means that those links will be turned into a dynamic link, and they will follow the Funnel Routing Settings.
On the other hand, the Link HREF is applied for the static links/pages when you create your webpage into the Page Editor. Likewise, other links such as the Terms & Conditions or the Policy work as Static Pages.
Please note that if the webpage is used in a Funnel builder and linked to an offer page with an action, which is different from the link you have added into the link HREF, these CTAs links will be replaced/overridden with the action ID in the relative funnel and go to the correct offer.
Identifying the CTAs has several purposes:
For CTAs, we track Clicks, B_CTR, P_CTR.
When replacing the URL for one of the CTA on the page, CTRwow asks users if they want to apply to all CTAs at once.