"How could this badly designed thing work if it wasn't so badly designed?"
Sometimes, if you can't make a thing work, the solution is to use something else that does. And sometimes the solution is just to make it better, like directing the IR detection beams just to either side of the water stream.
at the office we have the ones you have to push down--and hold for the water to run. i've encountered them elsewhere and you get 10-20 seconds before the water shuts off... ours doesn't. by the time you get your hand down to the water, it's shut off.
We had "sink bricks" to solve that problem, somebody was tired of those so they went to the hardware store and bought a couple bricks to hold the buttons down. Eventually the faucets were replaced with proper ones with normal valves.
This and most washroom faucets have too little space for washing hands. The space from the spout to the back and bottom of the sink doesn't allow for rinsing whilst scrubbing without touching the sink. Infuriating.
I wet my hands, get soap, scrub, and continue to scrub as I rinse. Not going to stand there for 2 minutes for all the soap to rinse off on its own. Your way is actually worse because you end up having to maneuver your hands a lot more to get all the soap off to the wrists. And good luck trying to wash your forearms.
They're not actually intended for washing your hands but rather for ticking the 'customer hand-washing facility available' box and providing jobs for interior designers nephews.
LPT: For faucets like this (or if you just want running water to wash something) get a paper towel. Wet it under the water and then put it over the sensor.