Yes, Yes. That's true and it's a useful app. But in general, I like all my images to have little more details. So, an option to enhance the detail will be quite helpful. Also, manual mode can give you more control.
iPhone being the most used mobile cam on earth, I think, manual mode will be appreciated by photographers or hobbyist photographers.:angel:
Manual Mode won't help unless Apple gives the user the option to control the compression the camera software does to JPEGs/HEIC, and disable lossy DNG compression.
A good exercise:
Take an iPhone 6S/7 and a Galaxy S7/S8 and take equivalent photos of the same scene from the same angle (use a tripod) in different scenes, then compare the imaging output... A few things jump out immediately:
1. The iPhone is lacking when it comes to details in the image - particularly fine background detail.
2. The iPhone JPEGs are significantly smaller than the Galaxy JPEGs (more aggressive compression). This is because Apple's camera software favors space optimization over quality. In layman's terms, Apple intentionally makes your photos look worse to save space, and in the age of 64-256GB iPhones, the trade-off is definitely not "reasonable" (IMO). Not when you can buy a different phone and take better photos, even on Auto.
3. DNGs produced by iPhone apps (using iOS APIs, so I don't think the camera apps themselves - ProCam, Camera+, etc. - are the fault of this), are significantly smaller than those from the Samsung handsets. Often, they're almost half the size... This means that Apple is also using Compression for DNGs. When you look at the DNGs from the two phones side by side (in Adobe Photoshop Lightroom), it becomes obvious why...
Apple is using LOSSY DNG Compression.
Pro Mode won't fix that, if all they do is offer ISO, WB, Focus, Saturation, etc. adjustments. Those are not the things that bug more "Prosumers" with the iPhone camera. If you want more detailed images, then you need a way to avoid the compression the camera software performs. DNG was thought to be that way, but Apple does Lossy Compression on the DNGs, so you end up doing a ton of work for results that are only marginally better than what the camera spits out...
Pro Mode on Android flagships work because the Android Phones which provide it allow you to use tons of manual adjustments on top of giving you the ability to spit out full, uncompressed RAW (DNG) Images. This can result in images that no iPhone can match, regardless of what Camera App you use - and even if you set it to output TIFF or Apple's [crappy, lossily compressed] DNG output.
You could adjust WB, ISO, Saturation, etc. before Pro Modes were a thing. That's not the "answer" to your specific complain.
Additionally, it pretty much doesn't matter if the iPhone is a more popular camera phone, as many (if not most) of the people taking those images are not concerned with photo or video quality. These changes were spurred on by Apple's reluctance to move to higher base Storage SKUs for too long, putting too much pressure on users who had lots of photos on their devices and running into issues with iOS upgrades, etc.
It must also be noted that a lot of this came relatively recently... I think iOS 8 was when users really started complaining about this, but it became much more noticeable after the iPhone 6S was released (which increased the camera resolution). Because the image resolution went from 8 to 12MP, Apple ramped up the processing and compression on those camera to keep image sizes in check.
This resulted in higher image quality degradation, which is why many people noticed the disparity. This also means that users never really benefited from the increased resolution! Apple completely canceled out (and then some) any benefits from it by ratcheting up the aggressiveness of their software processing. They compressed away much of the benefits IRT detail resolution in images... So the increase in resolution was less of a benefit in practice. It was just introduced to, again, fill in a check box on their spec sheet and say that they could do 4K video, too.