I wouldn't write them off because they were late once. Sh!t happens. If they're regularly late, then yeah....
Can you live with a bit a lateness if the material/musicianship/personalities are good? Our singer always turns up at least 40 minute after the rest of us, but by then we've had a jam and often got some ideas cooking.
Or would you rather play with a bunch of punctual idiots with crap songs? 😝
Personally I'd give it another go and take it from there - problems tend to rear their heads fairly early. You'll know soon, I reckon...