I learned about this not too long ago and think it's a good thing. Grant Fritchey touches on this in his excellent book, SQL Server Execution Plans (page 162):
Since the indexes that define an indexed view are available to the optimizer, they are also
available to queries that don't even refer to the view. For example, the query in Listing
4.13 gives the exact same execution plan as the one shown in Figure 4.17, because the
optimizer recognizes the index as the best way to access the data.
-- Itzik Ben-Gan 2001