How bad is a 640 rating

Same here I am 618 but i crushed my friend who is 1300 in chess.com in 5 win out of 5 games

It's better then a lot of people realize and is arguably eight in the middle of all players in terms of skill based on chess.com average rapid elo. It's the beginning of the level that most people who play chess think is good that don't play competitive chess or a lot regularly on chess.com and is about 400 uscf. And is the level people where people start consistently seeing Skill and the ability of someone who's got some skill and ability and knowledge converting consistently on tactics, trading and checkmate patterns, making them among non club and non competitive players sometimes the best in friend groups or families and in scholastic clubs. When i was scholastic there was a player who was 600 uscf that i struggled with but eventually figured out how to beat but it took me a year to get consistent against him. This level extends up to about 600 uscf I'd say and then it takes a bit of work and consistency to get to 800 uscf and not fall prey to 600s and 600 errors in terms of board vision and seeing forks and not losing material on exchanges or to basic checkmate patterns like scholars or corridor or the queen on h7 with support and to develop well so one doesn't lose to bad positions in terms of center board control. 600 uscf is probably about 800 on here. 800 uscf is probably about 900 to 1000 on here. and a beginner rating is more like 200 rapid on here. So anyone who thinks 600 is a beginner is wrong arguably and been listening to higher up level prodigies who have forgotten what it's like to be low and or never were because they flew thru the levels.