(Referring to prebuilt versions.)
While I do not own one (yet) myself, I keep wondering: since it has only volatile memory, the seed needs to be entered every time, through QR scan. That in itself is a huge risk. I would not want such a risky QR code laying around.

Is the version with the card reader better? It would allow for encrypted storage of my seedphrase.

How much money is enough to make buying Bitcoin worthwhile?

What would you consider the minimum amount of money to invest in Bitcoin for it to be meaningfully profitable or useful as a long-term hedge/store of value? At what amount does it actually start making a noticeable difference?

I don't mean large amounts, but amounts that an ordinary mortal can afford.