<
> On the other hand if you just want to store the coins long term, then HD-wallet doesn't give you ANY additional security. Actually the opposite, because your HD wallet could break and you could lose your coins. And if you save your HD wallets seed phrase, how does that differ from paper wallet?
And of course you could get a HD wallet that has been tampered with. <
>
I find it does. For example, I could keep a hardware wallet offsite (i.e. a vault, or someones house), whilst having peace of mind knowing that it is protected by the pin code (and the three bad consecutive attempts -> reset feature). Id prefer storing long term crypto in a physical hardware wallet that a paper wallet, although ultimately the weakest point will be the safety one sets around the 24 recovery phrase itself.
If you purchase the hardware wallet from the official sellers store (i.e. Ledger, Trezor), chances of pre-tampering should be close to cero. Its when you go outside the official channel that chances increase (i.e. purchase at eBay, unofficial resellers, etc.).
Paper wallets can also be tampered with (even more so) ,depending on the software you use to print it with, and data is easier to retrieve in it falls into the wrong hands than a hardware wallet.
As to when to purchase a hardware wallet, Id say as soon as possible, since it currently is the safest storing method. I bought mine before making any crypto purchases.