It may work ‘fine’ but really, a system with more memory works better. 5 browser windows/tabs and one video is not really a demanding workload and that’s already using over half of the machines resources.
No it is not a demanding workload. If you have a demanding workload I absolutely recommend purchasing more than 8GB of RAM, And Apple will gladly sell you a machine with more RAM if you need it. But for the vast majority of people 8GB is plenty, so that is what they offer on their base machines.