FWIW, that user experience is most likely Coinbase, or something very much like Coinbase. Not only is the UX good, but customer funds are taken seriously now and have been for a long time.

Coinbase still has custody of customer assets, though. That's what has to be either eliminated or insured to avoid trouble.

To avoid what trouble, specifically?

If it’s risk of customer funds mismanagement, coinbase is just not in the same galaxy as the folks who have blown customer trust.

If it’s securing funds, to prevent hacks, CB offers cold storage. Lumps of crypto can be transferred out of their control as needed to manage risk.