The big deal is that you are coerced into giving up extremely detailed and personal information. Your face at a security checkpoint or gate does not look identical to your face on your passport. Happy, sad, frustrated, tired? Last time you shaved? Stubble or beard? Hair in a mess? Glasses? Use and style of makeup (for women)? Dental status? Stained teeth? If you're dumb enough to smile or if they force you to in the future (for "security reasons")? One or more pimples?
All of the above is contained in a SINGLE photo. MULTIPLE such photos every time you fly tell a whole lot about you. Way more than I'm comfortable giving up to companies and governments I don't trust will handle the data responsibly.
So you’re concerned with the number of photos with regards to tracking even though the government already has your ID with your photo and they can easily find out everywhere you went if you carry a cell phone?
I’ve gone through security over a dozen times in the last year and never had a problem with it recognizing my face. My wife changes hairstyles very often and it doesn’t have an issue. These are solved problems.
What extremely sensitive information? Your photo they already have?
If you don't understand the difference between ONE photo and DOZENS of photos taken over several years, I can't help you. Go troll someone else.
And what exactly threat do you think you are avoiding by not having more pictures taken of you? Honestly,if you carry your phone around with you or using credit cards, worrying about extra photos is completely non sensical tin foil hat wearing territory.