So does my Bosch dishwasher, I think.
I've fed it on the tablets I use in the water softener, with no ill
effects, as yet (5 or 6 years).

I just plumbed my dishwasher into the soft water, so there is no need to
continue feeding the dishwasher at all. The main problem is finding
dishwasher tablets without "salt action". Unfortunately, what "salt action"
actually means is that the tablet is full of environmentally damaging
phosphates. Quite frankly, they should be banned. It is ridiculous that we
are pumping out all these phosphates just because people can't be arsed to
fill their salt container.

Salt is salt. In reality, it uses a brine solution and I can't see how
the shape of the solid salt will affect operation.
Anyone saying otherwise is usually in marketing.

No, there is a genuine reason. It affects the accuracy of brine metering. If
the brine is metered by level, rather than flow, having a consistent size of
solid salt in the tank will ensure that the amount of brine up to the level
is consistent. Whether that accuracy is of much concern is another matter.

Christian.