You are right. They are definitely not ordinary consumer products. However, they might be useful where recharging or exchanging a battery is impossible or associated with serious disadvantages.

For example, in the past cardiac pacemakers had been used with nuclear batteries. However, there is a risk that the pacemaker will be “forgotten” after death, and something that is actually radioactive hazardous waste will be disposed of via crematoria or cemeteries.

Another area of application for nuclear batteries is space exploration.

I think the tradition is someone else's pocket in some other country.