We used to keep medical records on paper in huge filing rooms. Then when the internet came along we moved everything to digital records, but we still kept the paper records just in case.

Now, everyone has shredded the paper documents as we've become comfortable with digital.

I think the same thing will happen with bitcoin self custody. It seems scary now, but over time we'll all get used to it and it will seem like no big deal. In fact, it will be the normal. An ETF and/or relying on others to manage your wealth will seem absurd.