Here is how to think of this problem.
Suppose you are going to buy 100 tickets. You have two options. One is to buy 100 tickets that all have the same numbers: Let's say for example you buy 100 tickets that all have the same 5 white balls and the same mega ball: 5, 10, 20, 25, 30 MB: 35.
What are your odds of winning? What advantage have you accrued for $100 over spending just one dollar?
Granted, if the drawing comes up 5, 10, 20, 26, 31 MB: 36 you will have won $700, but if your numbers come up for the big one, you will have 100 shares of the jackpot, which is irrelevant if, as is most likely given modern odds, you are the only winner of the grand prize. (Very few Mega Millions or Powerball drawings produce more than one winner these days.)
It is true that you cannot raise your odds of winning the lottery on any one ticket. But you can, if you buy more than one ticket, say n tickets, it is possible that you will not reduce your odds by 1/n. The actual reduction may be less than you expect.