Not my experience at all. Perhaps your phone's privacy/security settings for the app could be causing problems? I have to remember to change settings when traveling for the digital key to work, for instance; my default for every app is to disallow anything not absolutely necessary (applies to IHG and Hilton apps as well, not just Marriott).

cheers!

PS - are you using a VPN? That really messes with things. Some time ago, I had a subscription to one for about a year and quit using it—so many things wouldn’t work with it enabled the frustration just wasn’t worth the hassle. Apple’s Private Relay is marginally better and much easier to toggle on/off—nearly always interferes with initial connection to hotels’ wifi and definitely stops the electronic keys from working IME. So either of those might also be interfering with app functionality for checkin/checkout.

cheers!

If the desk is attended and time or line length is not an impediment, and frequently one of those is a problem, I always say "both". Even though I'm having a near-perfect success rate with electronic copies. Paper can still be your friend, and it has worked magic say 2% of the time in the last 40 years.

But I'm old and paranoid. Belt and suspenders still sounds like a good plan to me. (Which strangely has become a bit standard for young men with stomachs and old men with skinny rear ends). If it were up to me I'd probably throw in velcro on the waistband too.

Very YMMV for me. Doesn’t reliably work IME. If on a work trip I always ask for a printed copy - been burned too after with Marriott not sending it by Email.

You should get the folio even before leaving the property, in the the middle of the night on checkout date. Additonal folio emails will follow after you check out, or after the hotel checks out for you.

Online checkout works for me faultlessly, but never online checkin — i.e being able to check in and bypass the front desk entirely on arrival. I asked a few times and was told that they needed to see photo ID each time, no matter what details they already had on file, or how frequently I stayed at that property.

This was at London St Pancras. If online checkin works elsewhere I’m curious if this is a per-property policy

Countries have different requirements for presenting identification at hotels.

As do different hotels within the same Country. I for one and not a fan of fully automated on-line check-in and am fully in favour of everyone having to pass by the front desk to show ID. While perhaps slightly inconvenient it's a small step that could help against human trafficking and other potential illegal activities from taking place at the hotel. It also protects against activities that go against the ruled of the Bonvoy program, like booking a room with your points for someone else to stay in.