The fact is that beta batteries have been around since the 1960's, and for the reasons you've described they're not really useful for commercialization. I'd add

The fact is that beta batteries have been around since the 1960's, and for the reasons you've described they're not really useful for commercialization. I'd add that even if they were somehow absolutely foolproof, you'd still need strict regulatory oversight of disposal/recycling. The cost would be immense, the benefits would be slim at best.