If they are e-gift cards, chances are higher for hackers to get the value (but typically you can call the company to get a refunded gift card).
If they are physical gift cards, chances are higher that you'll just lose the card somehow due to carelessness etc (not much chance of hacking if you don't register the physical card online, but if you lose the card its gone like cash).

You can take the risk if you want, and I would for a lower value (up to say $3-5k) - basically the risk isn't very high, but its there, so only buy an amount that you can afford to lose without jeopardizing your renovation projeft.