There's a "50% off launch offer" banner everywhere. What's the catch?

From what I can tell, no catch — it's a launch promotion to get photographers in while the platform builds momentum. The discount, along with the free trial, is applied automatically at checkout; you don't need a coupon. The pricing page is careful to say the prices shown are the original ones and that offers get applied at signup, with the final amount you'll actually pay displayed on the registration page. So the number you see in the end is the number you pay, no surprises later in the process.