I agree with what has been said, but I would like to add some other considerations.
The B4X language you have to learn to program Android devices, is the same language you have to learn to program
iOS devices, Arduino devices and Windows apps. One learning task for opportunities on four platforms.
Moreover "learning" while not always easy is always beneficial. The mind's ability to abstract is amazing and the more you assimilate
the more effective that abstraction becomes.
Learning to program in any coding language is learning to break things down into procedural steps that can then be implemented
at lightening speed. Why would that not be worth doing?
I actively seek out new learning opportunities each day. I give an example.
When I was at University I had a friend who regularly beat me at chess.
It was not important to me at the time, it was just an interesting activity to pass time.
When I retired, I decided to test an idea that if you do a task repeatedly without too much analysis, in time
the solving process would become integrated into the mind, and eventually I would become better at chess.
So every day or so in the past 10 years, I have tried to solve chess puzzles, trying to make as little effort as possible.
Sometime even reading a book at the same time, making a move once in a while.
This week I actually paid attention to what I was doing and voila, it was obvious that I knew most of solutions right away.
I have learned many coding languages, as have most of the members of this forum.
For me, and I am not alone, I stick with the one's that are most "fun" (least annoying).
Since finding the B4X language, I have had lot's of fun, been very productive creating apps, and have been able
to apply what I learned to make Arduino robots that can communicate with the desktop and with android devices.
And yes I learned to solder.
You can create web apps and servers with B4X and fantastic charts, graph, and games.
None of that is dependent on whether smart phones will continue to exist in their present form.
Even AI entities need material to learn and verification to be useful.
My advice to all is be open to new ideas - you won't be sorry.