Because every Lightning wallet is a hot wallet. Coldcard Q holds the private keys offline, and is therefore a cold wallet.

Ah, now I get what you’re asking for. The reason that you can’t buy hardware from @Coinkite over Lightning is because @DETERMINISTIC OPTIMISM 🌞 and @DocHEX doesn’t like the trade-offs and downsides with accepting payments over LN. Source? The @Bitcoin.Review Podcast.