They're just different sports. Conor's style has been developed for a fight that allows kicks, needs to respect the takedown, and generally has lower quality strikers. With training he'd surely be a competent boxer but this is his first time competing in boxing and he's going against one of the best ever. I heard a Dave Chappelle clip recently where he summed it up surprisingly well with "Floyd's been training for these last few months while Conor has been learning how to box"
No matter how well Odell Beckham runs routes, he's not going to be running any iso plays against Lebron James any time soon.