No, I will not buy if I won the lottery people where I bought online can easily trace me as their winner, it's better that you buy your own ticket online because your privacy is safe, there are people here that offer people for their service and that is buying a ticket for them for a small fee, but what if they record your ticket, they will know exactly that you've won the jackpot.
If you can do it on your own, then its better to do that and youre correct about your security. If you ask someone to buy for you, then you might need to pat the fees which can cost you more. I would only buy using my bitcoin if Im sure about my security.