you know...if it can be transpiled by babel that means you could write it in es5 compatible syntax...yourself...so if you don't want to use the babel tool chain...what's stopping you? Don't know es5? IMO it's not too fun compared to es6...but...
Yes, so do cooks at crappy dinners and bars. This audition is also often unpaid, sometimes called a "working interview". I've known people who have gone through this in the last few years for jobs making just above minimum wage.