As long as you choose to play at a licensed online casino, it is perfectly safe to use LTC for online gambling. The casino’s licence ensures that games are fair and that the highest security standards are met. In reality, gambling with cryptocurrencies is no different from regular online gambling.
Just make sure when you do a Litecoin transfer (or any crypto transfer) to get the address right. Otherwise it will be near impossible to track your funds and recoup them should you make an error.
Also, of course, keep your LTC safe by storing it properly. Many would say hardware wallets are the most secure option for storage in general. Though what’s called a hot wallet is often better for storing crypto that you’re planning on using in the near future for casino gambling or other purposes.