De-ionised water is often better than distilled water, although ideally for the purest water it should be de-ionised then distilled.

Most laboratories use de-ionised water not distilled water these days and often what is sold as distilled water is actually only de-ionised. So yes a good de-ionising column is ideal for photographic use.

The filters you linked to are just that a particle filters so not ideal although useful. A simple water filter used to soft water to prevent a kettle furring up is quite adequate with UK tap water.