Let the record state that I am not a fan of the plastic hotel room key card.

I lose them. I confuse them with credit cards and I fumble trying to figure out which way the card goes into the lock. They demagnetize, usually on the 25th floor of a large Las Vegas hotel with a long and slow-moving line at the front desk.

Most hotel room doors today are opened with the ubiquitous plastic key cards. But a surprisingly large number of hotels worldwide still use metal keys, of various vintages, attached to creative and sometimes (by design) very heavy key fobs. The ease with which key cards can demagnetize or otherwise malfunction is just one reason why a large number of hotels worldwide never went plastic. Another rationale: security.

In January of last year hackers attacked the computer systems at the Romantik Seehotel Jaegerwirt, a traditional hotel situated on an Instagram-worthy lake in Austria, invalidating guests’ key cards and preventing management from issuing new ones. The hotel had no choice but to pay a ransom in bitcoin in order to give guests access to their rooms.

To guard against future attacks, the manager told the New York Times, he was considering replacing key cards with old-fashioned door locks and metal keys last used when his great-grandfather founded the hotel.

“The securest way not to get hacked,” he said, “is to be offline and to use keys.” What’s more, electronic key card locks don’t always work as intended. On the third and last day of his stay at the W Hotel in West Hollywood, Calif., last year, Sidney Chua, a New York-based financial analyst, discovered by chance that the door to his room hadn’t been locking even though it “clicked” shut. So presumably anyone could have walked into his room and created mischief. Attempts to fix the lock failed and Chua was moved to another room (unbelievably, the hotel refused to offer any compensation for putting Chua and his valuables at risk). How many people check to see if hotel doors have successfully locked when leaving a hotel room? (I do now and just in case I suggest that you do, as well.) And earlier this year, Finnish security experts discovered a software flaw that allowed them to create a master key card from any hotel key card, even an expired one. The hackers reported the flaw to Assa Abloy, the world’s largest hotel door lock manufacturer, before it could be exploited by criminals, and it has been addressed by a software update, but hotels must install it individually and not all will do so.

It turns out old-fashioned metal keys and locks are pretty reliable, even after all these centuries. And yet, hotel managers have told me, it’s not security concerns that have preserved the tradition of metal keys with fobs so heavy they could serve double duty in the hotel fitness center. They’re designed that way to coax guests to leave them at the front desk when not in the room. Melanie Volkers, director of sales at the historic Hermosa Inn in Paradise Valley, Ariz., notes that guests are “thrilled to get traditional keys (we won’t lose these!) plus the key fob contains a miniature flashlight” to help navigate the grounds at night.

Other reasons I heard from hotel managers who eschew plastic: Plastic is not eco-friendly and key cards aren’t always recycled; a key left at the front desk indicates to housekeeping that the guest’s room can be tidied up, eliminating those annoying knocks at the door; and finally, simply that the hotel is traditional and plastic doesn’t work well with the brand.

Sadly for tradition, soon most hotel room doors will be opened by your smartphone. No keys, no waiting in line, no “How’s your day going” at the front desk because in some hotels, there will be no front desk. Hilton already offers keyless technology at over 3,000 locations, and guests who prefer an impersonal and efficient check-in experience love it.

Until, of course, they leave their smartphone in an Uber, they drop it in the pool, or its battery dies.