I haven't tried the tablets - but they are homeopathic and I don't think that they will do anything 'harmful'. Homeopathics if not needed just don't have any effect.
Honestly, at your dd's age accidents at night are quite common. Annoying for the laundry person but normal.
With my kids we had to watch what foods/drinks they had later in the day. Chocolate and citrus made my kids wet the bed.