The easiest way for me to explain that is, you tell me how you create your paper wallet, do you use a live OS, airgapped PC etc what other precautions you take, and I'll explain based on that scenario how an encrypted wallet would be safer.
I'll bite. Within a faraday cage, assemble a PC from parts purchased and held in storage for the last several years. OS installed from DVD (let's say Windows XP, original discs). Wallet generator software source code printed code-reviewed, and re-entered by hand and compiled on the PC. Wallet initial entropy via dice, rolled in a darkened room in the dead of the night (sensitive fingertips required for dice reading). M of N paper wallet created and written by hand. Remainder of notepad incinerated. Pages stored in geographically disparate secure localities. PC degaussed, then incinerated.
If coins are to be spent, M parts of wallet gathered, then repeat most of the above, sign the transaction, transfer the signature via handwritten pad, and enter on the connected PC of your choice.
You didn't say it had to be practical.