The materials listed on the Wikipedia page and used by the Russians are not practical for large scale use. It's simply too dangerous to have that much weapons grade material or bone seeking material out in the wild. Some isotopes are better than others, and I expect there will be strides using specifically generated isotopes that are not weapons grade, are not bone-seekers, and have much short half lives (decade not 80+ years), and have beta decay.

What's the issue with Cs-137, then? The gamma radiation? Otherwise, is SrTiO3 really that bad? What's the risk there, someone stealing it for a dirty bomb?

can you clarify what you mean by bone seeking? i have a very rudimentary understanding of radioactive materials

Strontium has similar properties as calcium and thus ends up in your bones when ingested where it will cause prolonged damage. Hence bone seeking

He probably means beta emitters, which concentrate in the thyroid and bone marrow.

This is kinda what I envisioned when people talked about backyard small solar reactors. I wish someone was building a commercial venture out of it.