It introduces instability into your production environment, risks infecting your system with malware, and deprives developers of revenue. If you are serious about music production, the industry standard advice is to use the (which works with many free libraries) or save up for the legitimate license to ensure stability and support.
Regardless of the patcher, Kontakt 7.1.x can be resource-heavy. Here are a few "pro-level" content ideas for optimizing these versions: Kontakt 6-7-1 Patcher