Er, yes, he is. Biden has been a key figure in US foreign policy circles for over thirty years. He's worked extensively with America's allies in that period, whether as the leading Senate Democrat on the foreign relations committee or as VP (and before Obama selected him to be VP, he was regularly mooted as a likely Secretary of State). In diplomatic circles he's both well-known and generally well-liked.
None of which means you have to support him as the nominee or whatever, but it's nonsense to pretend he wasn't a big wheel on the world stage for a long time.
You listed his CV? I thought we were talking about how liked he is internationally. Internationally he is renowned for being a fucking creep, and being one of many established politicians who seem to be completely void of knowledge or talent.