I have a keypad outside my garage that activates the opener. Every time I enter the 4-digit code, I push the other 6 buttons as the door is going up, just to prevent this. (Obviously, if it were a communal area, I couldn’t make everybody else do this, though.)
I think the theory with the backup keypad is that it wouldn’t get used enough to show evidence of which buttons are used - we are talking about a system that’s normally supposed to be accessed through the smartphone, after all.
Myself, though, I’d be more concerned about the locks getting hacked. Not by some dude sitting there carefully watching you and doing Haxor-style two-keyboard typing from a van outside your building - but instead by downloading the exploit which somebody found which opens every single lock released by the company. Which exploit he then uses to lock out your phone and change your keypad code, all from the comfort of his apartment in Korea.
I guess I’m just not as paranoid or privacy focused as some people. I simply wouldn’t care if my landlord knew every time I entered and left my apartment. There’s days when it’s frequent and days when it’s not.
In my building, there’s a key fob to get into the building, but they’re not unique to my specific apartment. Often, the concierge at the front desk will buzz me in anyway without the fob. My apartment itself has a standard key, but I’d be fine with using an app to open the door instead.
I just don’t have time to be paranoid about someone hacking a database and getting electronic access to my apartment and robbing me blind. There’s lots of things that ‘could’ happen and I just don’t have time to be paranoid about everything. The last time I had someone steal from me, it was from someone who I’d let stay with me. I figure that situation or just random criminal acts are far more likely than some master criminal hacker getting a universal access code and breaking into my apartment.