It's not just better worker protection. It's the whole system that has more social safeties for everyone.
You might be better off with better conditions working for a top American company but you are not most people, you are part of a privileged few who had the capacity (opportunity, financial, intellectual) to be part of a a select who can enjoy this position.
You're also dependent on your company to provide these benefits.
Having competition from company on benefits is great for everyone but there must be a minimum for anyone in a society to be protected against predatory companies and to not have to work multiple jobs to feed their family.
Having a minimum of protection, knowing you will get support if you lose your job, get cared for if you get sick and when you get old, have an education that is not financially elitist, make enough to live -modestly- and feed your family on a single job,... these are worth a lot to a society.
Everyone is free to argue the cost of that of course, but it's a way to reduce disparity and the risk of poverty.
No system is ideal, and if you are lucky enough to have your skills in great demand then you have a chance to make a very decent life for yourself. For most people that's not really the case though and it's shouldn't be left solely to the randomness and kindness of the company you work for.