In most? all? of my jobs, I've gotten a free life insurance policy for, I believe in all cases, 1X my salary. There was usually an option to buy more, conveniently, through payroll deduction. The premium was independent of age. When I was considering it, premium for the "extra" employer-provided life insurance was not terrible at all, but nevertheless not as good a deal as the term insurance I bought from TIAA-CREF, from SBLI, and from the Wisconsin State Life Fund. My recollection was that I did opt for an extra 2X salary for a few years, just as a temporizing measure, before I bought the other policies. Check off the box first, one less thing to worry about, then price-shop later.
Employers decide what package of salary and benefit to offer, based on whatever considerations they consider--probably what's customary and competitive. A small but worthwhile amount of employer-provided life insurance is so customary that, yes, it would raise my eyebrows if a prospective employer failed to offer it. I think it's a decent little freebie, and I suspect that the insurers are willing to cut good deals with employers based on the the likelihood that many employees will opt to buy some extra insurance.
Annual income twenty pounds, annual expenditure nineteen nineteen and six, result happiness; Annual income twenty pounds, annual expenditure twenty pounds ought and six, result misery.