Smart girl. Looks like she's Canadian so depending which province, after tax lump sum would have netted around $500K or less. $1k/week would net around $45k/year, basically a married couple social security check starting at age 20. That's not baller but it's a great security blanket on top of whatever else she earns throughout her lifetime. And of course she can invest those checks as they come in.
She also possibly wanted to remove the temptation of blowing the lump sum on stupid shit over the near term (as most lottery winners do).
If taxes weren't a factor, lump sum is mathematically preferred but even that's not a no-brainer depending on investment risk tolerance and spending habits.