i used to do that with ribs when i had my charcoal/wood burner. gotta be really careful not to let your fire go out if you do it that way but it comes out nice. too much work fiddling with it to maintain the temperature though.
with the pellet grill, i program it to stay low (like 205-215) for the first few hours with a big brisket so that i can start it before i go to bed and it's ready for supper the next day. for me it's definitely worth a little extra money to get one you can program and monitor remotely (just don't forget to keep the hopper full).