But only because people want me to and pay for it... I wouldn't inflict the trauma that is using these on anyone.
I had problems with every single Android I owned, here is the current one:
1. Super slow, even after reformatting everything and reinstalling, it is not even a cheap phone.
2. Terrible interfaces overall, specially as they keep removing physical buttons, and apps started to shove important buttons (like "menu") in random places.
3. The interface thread seemly is prone to freezing, for example yesterday I wanted to use youtube, and the interface froze, and then suddenly opened a video I didn't wanted, and started playing full blast volume and waking people up, and I couldn't figure how to close the damn video, and then suddenly it crashed.
4. This all applies to the actual phone parts... more than once I had to quickly dial someone for some emergency reason (not life or death, but still emergency), and the phone app decide to be slow, or crash, or reboot, and so on.
5. Had the phone app crash on me while I was actually talking to someone.
And this is just my personal phone, in other phones I had one that I had to reinstall and the phone antenna stopped working after the reinstall (it needed a custom antenna driver, that I had to track down on internet and install...), random reboots, slow, extremely fast draining of the battery, specially if you made some mistake like leave a GPS-enabled app running, nevermind the fact that the OS itself is so crap, that every manufacturer ship the phone with several third party apps to fix OS problems (memory managers and defragmenters, app killers, temporary file cleaners, and so on...)
iPhone has another set of problems, but still is problematic. I personally would never buy one (my current client I am testing his iOS code on a device he provided to me...)
I have been very happy with Nexus phones (going back to Nexus S), and have never experienced any of those issues.
We also have 3 Motorola G phones - which for the money (<200) are really hard to beat. Motorola seems to have not attempted to mess with the stock O/S all that much..
First off, file access is mediated via software on the Android side. What you are seeing is a database representation of the device FS. And this database can be incorrect (people have in the past deleted folders they thought were empty only to lose files) or used to implement DRM.
Second, it is bloody slow.
The one benefit of MTP is that Android do not have to unmount the FS you are trying to access.
For the longest time MTP & Linux was terribly painful, verging on unusable, while mass storage worked perfectly. It bit when I upgraded my Nexus phone and discovered I couldn't get to the files stored on it.
Fortunately, all seems to work well now.
But oh my goodness! MTP support on Linux was terrible for a while, and even on Windows it wasn't fast and reliable. It was easier at the time to just use a service like Dropbox to transfer files to/from the phone, than to use USB.
I plug my Android phone into my Linux laptop. The phone's filesystem is mounted. I move, copy, delete whatever music and photos I want. Dead simple and rational.
I put Flickr on the phone. Photos I take with the phone are automatically backed up to Flickr, and I can see them from anywhere.