The advantage of a hardware wallet is that, come spending time, it provides a layer between the signing keys and the transaction broadcasting device. Additionally a hardware wallet gives you a seed mnemonic that you can put into any other hardware wallet if the device itself breaks. If you know what you're doing, you could even just use a seed mnemonic now and put off buying the device until it comes time to spend your funds.
If you just pop your private key from your paper wallet into a PC or phone that's compromised, you lose everything. Additionally, if you don't spend 100% of your funds, and the software you use for spending sends the change back to an address that you don't record the private key for, you'll lose whatever funds you didn't spend.