We’re in the same position. I’m currently living in Ecuador and she is Ecuadorian. For us, the reason we’re considering it is because she needs a visa for just about anywhere we go. I need to stay in Ecuador for at least a couple years for my Ecuadorian residency but it may take nearly that long to get her the visa anyway. We’ve got an appointment in a few months for a tourist visa since we sincerely don’t have plans to move to the US. The lawyer told me that I should expect they will deny her a tourist visa but at least with that we can travel to the US and a number of other countries. It’s really strange that with a US tourist visa you automatically have access to like a dozen more without needing to apply individually.
The real problem with applying for US permanent residency or citizenship is you now have to file US taxes forever. Not much of a concern for her low Ecuadorian salary but certainly something to consider for others that may have more assets or income.
I really love this idea. So happens her bother lives in the UK. Even though they’re not part of the EU anymore she hasn’t been able to spend much time with him and his family in recent years. Bonus the Spanish passport is even stronger than the US.