Index Design Recommendation - Examine Column Uniqueness

I am reading "SQL Server Query Performance Tuning Distilled",
on page 104 it talks about one of the index design recommendations
which is to choose the column that has very high selectivity of values
instead of a column that has very few selectivity of values.

My question is if I have currently indexes on my tables that have
1, 2, 3, 4, ... values only on thousands of rows, are these nonclustered
indexes pretty much useless indexes that I should get rid of?

And I know that pretty much the number of selectivity values will
always remain very low.

Thank you