Surely if you want to shoot professional footage, you use a professional camera, with an actual lens, with a full frame sensor - not something which has been scaled down to the extent that it relies on digital hallucinations to make an acceptable looking image.
Surely if you want to watch movies, you go to the cinema, with an actual projector, with a full frame film - not something which has been compressed down to the extent that it relies on digital trickery to make an acceptable looking image.
Turns out the recent iPhone camera hardware (especially in the Pro models) is simply good enough to shoot 'professional footage'. Not everywhere, not all the time and especially not in all lighting conditions - but it is good enough more often than not.
If you have a real professional bank account, you own (not rent) all the $100,000 camera systems you could possibly want (5-10?), but for everyone else, money is fairly limited. To be able to take advantage of the video cameras you do have to get extra camera angles for a scene, configured with the proper settings - ISO/shutter/white balance, is easily worth the $50 tripod and using your phone.
100k is a cheap pro camera such as a 50k will get you a Red 8k package but minus the frame and other gear to go with it. A Sony Venice 2 8K is 60k just for the main body. Lenses aren't cheap either.
Gyroscopic stabilization for iPhone is cheap and doable: DJI Osmo is <$100. 2 axis ones that run ~$200.
Real microphones with dead cat wind covers also improve indoor and outdoor interview dialog quality immensely. ~$100 item per person.
Most indoor lighting is shit for still or motion digital photography. Get real lighting and flood the scene. Lights are cheap, but take time and coordination to setup and tear-down.
One thing is brand onboarding: film students don't rent the big guns for everything and if they can do a quick "shot on phone" but with a blackmagic workflow, it will be hugely attractive for them. Think of it as cosplay if you like, but it can have powerful long term effect for the brand if new generations start out on their tools. Or in terms of computers, ca year 2000, think about it as leaning C++ instead of getting good at Excel VBA.
The other thing is consistency: if you do use the big ones, but have a shot where the big camera simply cannot be used, allowing an iPhone to stand in with processing defaults defaults set up to make the footage as consistent with the regular takes as possible can be worth a lot. Sony has created the RX0 line essentially for that, as a support gadget for their film cameras. Sales to consumers are merely opportunistic side income.
Same (super convenient to easily get consistent setting) for takes that are what in software development would be considered a bugfix, takes that happen when primary filming is over. All the rental equipment has been returned, the order of the day is getting least bad results with what you have. If blackmagic has tools for this contingency and competitors don't, blackmagic will be more attractive.
Depends on who you are and what you want to achieve. If you're a beginner and/or don't have access to professional gear, it's great to have a way of shooting "the professional way" on whatever you happen to have around. You get most of the manual control a proper camera gives you with an interface very similar to that of a Blackmagic camera, so when you finally find yourself in front of a real one, you already have some experience with it.
And while the image quality definitely doesn't compare to that of cinema cameras, 90 % of the time, it doesn't have to.
Steven Soderbergh made two movies entirely on iPhones. The first was with iPhone 8.
"Anybody going to see this movie who has no idea of the backstory to the production will have no idea this was shot on the phone. That’s not part of the conceit... There’s a philosophical obstacle a lot of people have about the size of the capture device. I don’t have that problem. I look at this as potentially one of the most liberating experiences that I’ve ever had as a filmmaker, and that I continue having."
why? I mean, with film, anamorphic Super35 is a thing, but so is Super16.
With digital, why would all the footage taken on professional MFT cameras be "not professional"?
Surely if you want to shoot professional footage, you use a professional camera, with an actual lens, with a full frame sensor - not something which has been scaled down to the extent that it relies on digital hallucinations to make an acceptable looking image.