Cursor and bulk collect

Folks,
Have a basic doubt in PLSQL. Why use a cursor fetch to bulk collect data into a collection - I had the idea that cursor gave control over the result-set. When i am bulk collecting data then what is the use of a cursor.

Moreover, if i have a complex query involving 2 or more tables with joins - can i do a bulk collect into a collection - all the examples were simple queries. i think we can. plzz correct me if i am wrong.

regards,
Prasenjit