On the other hand, we may develop a society where advancement does not depend on death.

That could prove really difficult without the death of those not in need of any advancement. Power and privilege by their very nature tend to find ways of avoiding being watered down.

As one still in need of advancement, I'd happily take that challenge (and that of continuing scientific progress).

Eternal life can always be abandoned if we find out it doesn't work.

A cure for aging is not necessarily a cure for beheading-by-guillotine