I think you skip a key point, while you may keep those keys you have to make them hot and there are other LN risks too. So putting them on the lightning network is not a zero risk move. It might be relatively low risk, especially if you're not a routing node, but you still have some nonzero and unpredictable risk. Even if its just losing sats to forced channel closes. So I see where you are trying to go but I strongly disagree. People saying lightning liquidity is risk free has led to an enormous amount of disillusionment and heartache around lightning. We need to be clear about risks and tradeoffs. Ask some LN veterans who ran self hosted nodes in 2018-2020 or during any high fee environment if you're skeptical.