Ask a better question than which format is better
Neither format is the winner in general. The useful question is what your audience does not know yet. If they have never seen your product and do not get why it matters, they need explaining and a video has the room to do it. If they already know you and need one more reason to act today, they need reminding and one clean frame can do that. The format should follow the gap in understanding, not whatever looks more impressive in a pitch deck.
When one frame is the smarter bet
A recognisable product, a simple offer or a visual before and after can carry a whole ad. Statics are also the fastest thing to make, which means you can put five genuinely different messages in front of people this week instead of one video next month. That speed is the real advantage. You learn which idea lands while the campaign is still alive, and you learn it cheaply enough to keep testing.
When a video earns its extra seconds
Some things cannot be explained in a still. A product in use, a messy process made simple, an objection that only disappears once people see it work. If your value needs motion to be believed, no static will do. But the opening two seconds still decide whether anyone stays, and most people watch with the sound off, so the idea has to survive captions and silence.
The honest cost of starting with video
The cost people worry about is money. The one that hurts more is time. A video concept has to be scripted, shot, edited and revised, and every change is heavier than moving a headline. If the message turns out to be wrong, you find out late and your whole testing window has gone. That is the actual risk, not the format itself.
The order we like: prove the message, then give it legs
Start with two or three statics built from genuinely different messages, not recolours of the same one. See which idea pulls. Then make that winner into a video with a hook you already know works, and let motion do what motion does best. Video becomes an amplifier for a message you have already proven instead of an expensive guess about what people might care about.
The quick checklist
Can someone understand the value in one glance? Start static. Do they need to see it work? Start video. Can you get three different messages live this week? Do that first. Never make a video to discover your message. Make it to scale one.