The officer is trained to take control of the situation immediately, and the citizen is required to make an announcement right off the bat. Two people in a tense situation trying to do different things simultaneously. Recipe for confusion.
I, for one, would not want to be the first to mention "gun" in an encounter with a police officer. I would certainly not yell it.
Texas concealed carry law requires a licensee to present his CHL when asked for identification, along with a driver's license if appropriate. That removes some of the competing priorites between the officer and the person stopped. The punishment for failure to notify has been removed, but the requirement is still there.
The officer may or may not disarm the licensee, at his discretion.
The CHL will show up when they run a Texas driver's license.
Just one more way to do it.