If what other people in here are saying is true and WTFast is a VPN(I'll admit, I haven't looked at the program itself. I honestly don't care much about this lol, just feel like showing off a bit), then the program makes it appear as if you are coming from somewhere you're not. Say you use Comcast and have a public IP of 74.12.12.12. When you connect using WTFast, you are connecting to a client-to-site VPN, which then routes all of your traffic through a device that they own. At this point your source IP is "translated" to the public IP of the WTFast device, so your 74 address now becomes, let's say, 161.5.5.5 for any traffic that you send out. This means that any traffic that's sent out from your 74 address has to go to 161, then the actual destination, then back to 161, and finally back to you.
Keeping this altered route in mind, how can this effect someone's ping? In some cases, if this new path ends up taking faster routes than the ISP(very common with overseas usage due to the clusterfuck of cross-ocean routing), it will be lower. If it ends up taking a longer route(Very much the large majority here. Adding an additional destination to stop at, a "hop", almost always increases travel time), it will be equal or higher.
The latter is more common because your ISP will, more often than not, have already established the fastest path to your destination and route you optimally. That's not to say that's always the case(For example, a "hop" reports itself as down, thus the ISP reroutes you down another path. You hear a lot of people from the mainland U.S. bitching about getting routed through Iceland and shit in internet backbone networking), but despite how bad their business practices may be, ISPs have their shit together when it comes to routing.
Lastly, a ping is NOT a direct translation of speed. It is the direct translation of the speed of a PING. ICMP(AKA ping) is a protocol that was not built, nor was ever intended, to actually relay data. Actual data, as in the traffic sent to and from Riot when we play the game, is transmitted over a host of different ports that are contained within two completely separate protocols that are designed for carrying data, TCP and UDP.
UDP, traffic that is sent directly to its destination without waiting for the other side to acknowledge a send request(TCP), is most likely what we use for League and other online games(source necessary, I've never actually looked), as to play in realtime we need the fastest transmission possible. UDP, like ICMP, travels directly to the destination and back to the source, 1 trip, which is why ping times are often used as a good indicator of in-game latency, though not exactly as the two protocols are extremely different aside from this.
I realize I'm being a bit pedantic here, but I just wanted to clarify for anyone wondering. All that being said, you wanted someone who understands how all of this works and you got one. Basic routing says that 95%(made up number, substitute "a large majority" here) of the time people will have increased latency when using an extra hop.
Of course, all this information could be completely wrong and useless if WTFast turns out to not be a VPN. Again, I don't care, just felt like showing off x3