I use desulphators all the time on my battery bank and use them to recover sulphated batteries as my whole bank was when i had it donated to me. In the dark ages i worked on farm 32 volt units servicing them on a 3 monthly cycle, this was the first time I came in contact with a desulphator it was given to me by the retiring gentleman who serviced the batteries for years.
While it is true that if properly managed you can get along well without a desulphator in practice this seldom happens particularly in the farming community, now I use them permanently on my batteries to keep them alive for as long as possible, my present set is 15 years old ex government building safety light set 1500 AH at 24 volts, it was originally a 240 volt DC system before I reconfigured it to 24 volts.
Advantages as I have found with desulphators, No need to waste a lot of power equalizing charge every cycle to get rid of sulphate and I believe this extends the battery life by not boiling active material off the plates, Also the sulphate is continually broken down from the crystalline state even when below float voltages, the frequency of the desulphator stops the crystals forming a blanket cover on the plates and internally in the microstructure of the plate active material.
There are high power desulphators meant for desulphating badly sulphated batteries in a short time, I do not believe these models should be left on the battery permanently but the lower intensity ones are OK to leave on.
As for interference with electronics a couple of my HAM radios suffered from noise from the desulphator so I put some ferrite beads on the battery leads and that reduced interference to a low level, lower than the PWM regulator.
All the best