I am about to renew my passport, and I got married since my last renewal. My country offers the option to include the marital status in the passport (my spouse and I chose not to change our family names).
Is there any practical advantage when the passport indicates the name of the spouse? I am thinking of situations such as customs & immigration, or perhaps common stays in hotels in areas where hotel rooms can only be shared by married couples.
I have never encountered a situation, where it would be an advantage.
Marital status field in the passport is not required or recommended by international standards, including those of ICAO. When proof of marital status is needed by the authorities, for example, for immigration purposes, they have a standard set of documents to provide as proof thereof, and the primary document for that is of course a marriage certificate. I think that it may be easier in most cases to show the marriage certificate instead of explaining that you also have that information in the passport. Marital status information in the passport may in some cases not be even considered as proper proof of that, unless specifically decided by court or relatively high-ranking official.
Unless required by local law, a major brand name hotel would not require you to provide proof of marriage. In some countries such as Qatar and Morocco, unmarried persons of opposite sex cannot share a room by law, but even there the best hotels don't require such proof from foreign guests.
If your passport only indicates that you are married, but does not mention the name of your spouse, if you are required to prove that you and your wife are married, that does not seem to be useful. In case of customs and immigration, they would probably want to see a document that shows the name of your spouse and not just your marital status. In case of hotels, if it happens that they require proof that you are married with the person, with whom you want to share your room, that would seem not useful as well, as you could be hypothetically travelling with your girlfriend, sister, or inviting a local female guest to your room. (Especially if you and your spouse did not change names.)
To summarize, I think that having the marital status indicated in your passport would not be useful, especially since the name of your spouse would not be indicated in the passport and especially that you and your spouse did not change names. If you think or know that you will be required to present proof of marriage, I would recommend bringing your marriage certificate with you (properly translated if necessary). Perhaps you can avoid hotels, where proof of marriage is required from foreign guests, but if the hotel, where you will be staying, requires such proof, it would be a safer bet to take your marriage license with you.
Furthermore, your passport is already a document with quite a lot of personally identifiable information, which is often used (especially for travel and international business), and copies of the passport may be taken for various reasons. Perhaps you would feel more comfortable if your passport contained as little personally identifiable information as possible in order to minimize the opportunities for identity theft.
