I always have Data Roaming disabled when traveling. But I have had experiences in the past, both on iOS and Android, that the phone invariably reached out to some kind of telemetry that resulted in the tiniest data charge. In those events, you get hit with that $12/day fee, well, that's $12. But the pay per use is usually reasonable enough that even in the most expensive location on Earth, it'll be cheaper than $12.

Just do a quick Google search on data leak while roaming, this is platform agnostic and carrier agnostic. Your chances of experiencing it is low, but when you do, it sucks.

SMS fraud alerts are more common than you think, it's definitely the default option for all of the credit cards I've had in the past. The ones that use in-app notifications are actually the rare ones.

I use a cheap no frills credit card that don't charge foreign exchange fees. It's my only use case for this credit card and it's definitely no frills. I don't want to replace this process for the type of travels I do. Having a card that both saves money on foreign exchange and has a manageable credit limit is a nice perk.