The answer depends on several major questions:
How much are you going to earn each year on that money?
How is it structured? (tax free or taxed)
What are your expenses monthly
What are you getting from Social Security
Is the house paid off?
I contend that a person who is receiving a upper end SSN payment ($3,000 / month) and has their house paid off, modest bills, and a $1M in a ROTH IRA will do just fine.
Someone who is receiving less SSN ($1,500 / month) is still paying off their house, has significant bills (medical?) and $1M in a bank savings account is not going to do so well.
THIS
You can’t put much as lump sum into an IRA though. When it comes time, I will be faced with where to invest.