I think that having a trigger on the button in the funnel builder would be useful because it adds a second layer of validation. Example, a link is added to the text and email sequences that will take the lead to the "Claim Offer" page with a "Claim Offer" button. The button would then trigger the opportunity to move stages from the "New Lead" stage to the "Offer Claimed" stage.
I've had leads accidentally click trigger links and claim the offer when they never claimed it. This trigger on the button adds a second layer of validation.