searching in by-gps albums doesn't find the subalbums (like searching in by-date albums doesn't find the months)
Actually, when the user searches in a by-gps album, he expects to find the subalbums too.
The reason why place albums are not searched is that only media and physical albums are indexed.
Place albums could be indexed too? one reason why not to index them would be the fact that place names depend on how they are put on openstreetmap; besides that, they would be fixed (at least in a quick & dirty implementation) and they wouldn't change according to the user language.
Obviously they should be found only if searching in by-gps albums