It's merely security theater.

It reminds me of when airports started scanning people's shoes because an attacker had used a shoe bomb. Yes, that'll stop an attacker trying a shoe bomb again, but it disadvantages every traveller and attackers know to put explosives elsewhere.

“attacker had used a shoe bomb”

It’s even dumber than that. An attacker tried and failed to use a shoe bomb, and yet his failure has caused untold hours of useless delay for over 13 years now.