1855 Spain O5-O8 (Cuba, Puerto Rico, Philippine Island)
Official stamps - Cuba EDIFIL 6-9
1855 - Spain O5-O8 - EDIFIL 6-9 - Unused, no gum. These Official stamps that had been in use in Spain since 1854 also began to be used in the overseas colonies, Cuba, Puerto Rico and the Philippine Islands in 1855. Traditionally, they have been placed in specific country collections only when used on cover or with at least, a clearly legible postmark from the country in question.

The seller adds the following to his description:

I personally have them in my Cuba collection in unused condition. My rationale for doing so is that many of the early CORREOS stamps were also used in Puerto Rico and the Philippine Island and we do not have any reservations about placing those unused stamps in our Cuba collection (I presume that Puerto Rican and Philippine Island collectors do the same). Hope you agree and put a set of these OFFICIAL STAMPS in your Cuba (or Puerto Rico of Philippine Island) collection.

Personally, no way will I pay this amount just to have this in the collection. Its nice to have but not a must. For $180.00 bucks I can get a very nice classic piece issued and used in the Philippines. 

In a postal history collection, why not? That is if one can afford the asking price for a cover. Assuming that affordability is not a question, the cover would be best placed in the Official Mail section of a postal history exhibit (the second to the last section with Inbound Mail as the last section, that is if one sticks to the standard method of presentation). Believe me, after mounting numerous postal history exhibits and seeing them on actual display, it will not be noticed.

The stamps and even an example on cover has no place in a Philippine traditional competitive exhibit as they were not specifically issued for use in the Philippines.