The biggest strength and weakness of Ubuntu Phone is that it's a device
without an intrinsic set of services. If you buy an Android device, you get
Google Services. If you buy an iPhone, you get Apple services.
What he's missing is that the device is pretty much useless without the
services. The services are as necessary to the functionality of the device as
say, filesystem drivers are on an operating system. Yes, it's possible to have
an operating system without filesystem drivers, but it's not going to be very
useful to your average consumer. Similarly, it's possible to have a smartphone
without location services, or push notifications, but it's not going to be very
useful.
While these can be strengths (at least in Google's case) they are
effectively a lock in to services that may or may not meet your
requirements. You certainly can get Telegram or Signal for either of those,
but they're never going to be as integrated as Hangouts or iMessage. This
goes throughout the device including things like music and storage as well.
I don't know what he means with regards to "storage" (cloud storage, perhaps?)
but when it comes to messaging, I find that Telegram actually makes a better
text messaging application than Hangouts. The UI is easier, it's easier to scan
through archived messages, and it's faster. That's leaving aside the obvious
privacy improvements that Telegram brings over Hangouts. Similarly, I find that
Spotify does a better job of handling music on Android than Google Play Music.
It has better integration with its desktop client, better sync, and it doesn't
lose its network connection when switching from wifi to LTE.
Android already has the strengths and disadvantages of Ubuntu Phone (mostly
thanks to Google's incompetence). I'm not sure what Ubuntu Phone brings to the
table that would make it better than Android. Right now, it appears to be an OS
like Android with many fewer apps, and even more headaches when it comes to
cloud services.