If you plug your USB devices directly into the wall, you’ll likely be fine. My process offers a higher level of protection because the high dollar devices never come in direct contact with the grid.
This was taken in India but I’ve seen this throughout the world. In Brazil, some structures in the favelas will quite literally be erected overnight and they will illegally tap in to the grid. Also, my description of some of the vintage generators was not an exaggeration. I’ve no way of knowing when they were built but they looked like relics. Added for clarity, I’m not talking about portable generators but the kind that you’ll find at hospitals, except really really old and sketchy looking.
For me personally, regardless if my concerns are founded or unfounded, my process works well and mitigates risk with almost no inconvenience.
Again, this is India but I have a similar picture from when I was in the Philippines earlier this year.

I couldn’t find the pictures of my exposed spliced wires but outlets in the showers are fairly common as often times that’s where the water heater is. Doesn’t seem to be a real problem but coming from the US, it earns a double-take.

Off topic, if you upgrade from the $7 to the $12 hotel room, you get a complementary floor bandaid.

Also, if you ever go to India, if you haven’t already, befriend Tom so he can hook you up on the must-dos in Jaipur, including this gem.

Since we’re whipping out our… passports… excluding transit countries and just listing places where I’ve at the very least overnighted and in some case visited multiple times or lived in for several to 24 months: Germany, Austria, Netherlands, France, Norway, Sweden, Denmark, England, Hungary, Czech, Slovakia, Bosnia, Serbia, Croatia, Cambodia, Philippines (my most recent), Brazil, El Salvador, Mexico, Panama, Pakistan, India, and New Jersey.
Edit: Almost forgot my favorite mayonnaise on fries country, Canada. ;)
Edity edit: I also forgot Peru, which I believe is one of the South American countries that uses both 110 and 220v depending on what region you’re in. It’s been several years and I don’t remember.
Edity edity edit: I should mention that I’ve never witnessed or known anyone who’s had a device damaged due to a spike/surge, but several who tried to plug a 110v only device into a 220v receptacle. My concerns are mostly a result of living or traveling through areas where what you see of the grid does not inspire confidence and the possibility of a short circuit immediately in front of or in the hotel seems reasonably possible, including being down the hall from a panel that started arcing as a result of a DIY project gone wrong by a maintenance guy who was in over his head. Fortunately only the panel was damaged and nothing that was plugged in downstream suffered.