Its technically safe but from what I can see in the features area of Edit:link removed , only the Pro version appears not to have Ads. Now programs/software with Ads usually means adware. While not all adware is spyware, a great deal are categorized as spyware. With this in mind, I suggest if you aren't going with the Pro version (which I don't believe has been released yet) that you be cautious of any intrusive ads or third-party installation programs/files. I personally recommend against this software due to it having ads at all and if you still plan to just use software instead of actual WiFi hardware, rather than using My WiFi Router, you can use WiFi Hotspot which has no ads and is easier to use.
Now keep in mind if you plan to do this for a while it can cause excessive heat for your WiFi chip in a laptop/notebook as well as for a WiFi USB Adapter. My suggestion would be buying a WiFi router for practical and permanent use. WiFi routers aren't that expensive nowadays.
Affordable WiFi Routers @ Newegg.com
Edited by dsenette, 29 April 2015 - 09:36 AM.