If a good physique (overall good looks) didn't matter Chippendales wouldn't be a thing. Look at what those guys look like - they aren't balding pot bellied guys.
As a guy it's hard for me to find other guys attractive. I have to remind myself that chippendale models are hot. That's what a lot of women look for. So yeah, getting into shape helps. I think it's 60-70% of a man's overall attractiveness. If a guy isn't classically attractive, he will still be able to find someone if he's charismatic, have the "right personality" that a particular girl likes, etc..
Physical attractiveness isn't the be all, end all for women; but it sure does help with initial attraction. And now that I think of it, since "flirting with a girl" or "chasing" a girl is somewhat fraught with danger - you know what they say, "it's only sexual harassment if they don't find you attractive". hahahaha... better to be more attractive.
Back in the day, you could be average and chase women; you could slowly make her like you, but the times have change. Talk to older married couples. A lot of times the wife did not initially find the husbands attractive at all. Now women are being told, if an average man flirts with her who she does not find attractive, that's sexual harassments. She listens to this, and look... the marriage rate is in decline... LTR are in decline. Oh well...