Why does crossing over take place at all?
Crossing over is believed to be beneficial for evolution. It does not cause only mutations, it allows for the switching and mixing of genetic information. Thanks to crossing over entire protein families evolved, like the hemoglobins. Indeed it is one of the mechanisms that shaped the chromosomes.
Some in-silico simulation proved that, in general, adaptation take place faster if crossing over is applied.

Here some extra references for further readings.

https://www.ncbi.nlm.nih.gov/pubmed/28565671

https://www.ncbi.nlm.nih.gov/pubmed/28564047

https://www.ncbi.nlm.nih.gov/pubmed/28563027

https://www.ncbi.nlm.nih.gov/pubmed/28557225

https://www.ncbi.nlm.nih.gov/pubmed/28555659