From the technical commitee of the Italian alpine Club wh did extensive drop tests on screamers using various belay devices. My translation.

"It was confirmed that the examined device has an ability to absorb potential energy, that is 120-130kgm (1.18-1.23kJ), as was seen from of the data of the drop tests executed on the drop tower with a fixed rope and from the dynamometer tests carried out in the laboratory. It was also confirmed that actuation (that is the rupture of seams) occured consistently for all the dozen of tests carried out at a load of ca.2.2kN. But, of more interest to the climber, it was also confirmed that it was insufficiently useful in the aim of reducing the load on the last runner, as is seen clearly from the results of the dynamic tests. In all the testing conditions in fact, the presence of the shock-absorber has turned out practically negligeable in the sense that the reduction of the load on the runner was nearly always insignificant, and additionally, in high force situations (ca. 8kN) and with
moderate braking force from the belayer the loads on the top runner were increased.
In light of its insufficient ability to absorb energy one thinks therefore that such device can be of guaranteed usefullness only when the total energy in the system is relatively low, that is in the event of heights of fall of few meters (e.g. a fall from ca. 1m above the runner)."

For aid climbing there could be a rationale, for the rest the belayer does the job.