I would say other than a bigger points bonus, the main difference is OW Emerald vs Sapphire. But even then whether that matters to you will depend on what airports you frequently access and on which carriers.
Like BA’s T5 Galleries First vs Galleries lounges? Other than better booze at Galleries First, they are pretty much the same (and equally crowded).
I am LT PLT and I ensure I get PLT PRO for OWE. I transit LHR several times per year and there is a difference. YMMV.