We always filed our taxes (jointly) no matter income or not, for immigration purposes - we did this before I even had a status in the US. It just felt a lot easier having tax return transcripts for ALL years. That was extra evidence of a bonafide marriage for both ROC and Citizenship, and we never had to deal with any immigration officer questioning us why we didn't file taxes some years.
I actually never disclosed my foreign income I got the year I moved to the US, neither did I disclose the condo I sold before moving. It's not like I made a lot of money, and I know it should've been disclosed, but we skipped it as it seemed like too much trouble. This was ~8 years ago now.