If you're already working with plutonium, whose dust is also very, very toxic (in addition to being radioactive), the additional danger of beryllium doesn't seem so great in comparison.

I routinely handled beryllium for a couple of years as it is present in certain electronic RF power amplifiers. It’s perfectly safe in solid form. If you drill it or smash it, a different matter!

Plutonium, not so much.

I knew a software engineer who made a lot of money in a startup and bought himself an ultralight bike of titanium and beryllium. They ceased the beryllium parts at the Canadian border and I don't think he ever managed to get them released to him.

I think only about 2% of the population is sensitive to beryllium. I was in a beryllium monitoring program (yearly blood tests) at work. A few coworkers are sensitive, one getting really sick.

Beryllium's also used as a neutron multiplier.