Two things I've read recently, cannot vouch for their accuracy:

1) Storing equipment with silica long-term can cause damage by drying out the internal grease that lubricates shutters etc.

2) Using the silica with colored moisture indicators can contribute to corrosion of delicate electronic and mechanical parts. Supposedly the substance added to effect the color change will off-gas under some conditions and it is very corrosive in this gaseous state. Can destroy delicate parts. This author advised using plain silica, not the indicator type if you use any.

These were two separate articles.