I've reread the OP and now clearly see the single word (!) which distorts the holy meaning of the whole thing and irritates the most of the commenters. I must immediately update it.
The OP title shall be now read as:
Why doesn't Stack Exchange reward some reputation points for installing & using mobile app?
I agree that rewarding reputation for solely using mobile app makes no sense as it doesn't generate any research effort for the Community. If I were you, I would also downvote this concept.
Another point - is installing SE mobile app, which definitely worth a reward to those who installed it. They might be one time rewarded with +5 rep.
A few examples of the concept:
- establish a new Dropbox account and get 2Gb as a reward.
- register Lufthansa/Emirates/Delta, etc. Frequent Flyer account and get 500-1000 miles start reward.
- establish an Assembla account and get a free repo up to 1Gb.
The true meaning of a reward is to stimulate users to use the services. Either ways. What currency does SE use to stimulate interest and activity? You know the answer.
_Original title and body_
Why doesn't Stack Exchange reward some reputation points for installing & using mobile app?
Imho, installing and using Stack-Exchange mobile app shows trust, interest and loyalty. Which is way more serious than just upvoting a silly comment.
This action shall be rewarded :)