I thought he was talking about connecting to +ASM using SQL Plus when the database is in startup nomount mode. It's not a traditional database in the it doesn't have everything that a traditional Oracle database has. But technically it is a database.
ASM functionality is controlled by an ASM instance and it is not a full database instance, just the memory structures.
My Doubt here is very clear, ASM information can be queried from diff V$ASM_% views. Whether those information can be queried from ASM Instance or a dependent database ? I dont have a test database here to do some exp