I would just participate for the fun, probably if I would win a tangible thing I would just open a raffle myself or give it to the second placed, I've also began to be a bit on edge about sharing the address especially after that Ledger fiasco where I got extremely lucky.
Ledger is a famous company in its line of business. Hackers and scammers had incentives to attack them, trying to retrieve as much of data as possible. Jambler is a popular brand, but it operates differently. It doesn't deal with millions of end clients like Ledger does. Shipping out physical items and storing client data in the millions isn't part of Jambler's business model. One should always be careful who they give their personal information to, but it's different in this case. Plus, most countries have PO boxes you could probably use for such cases.