Done wrong this will increase reflected energy at the feed point and make the transceiver run hotter than it is supposed to, possibly leading to an early failur

Done wrong this will increase reflected energy at the feed point and make the transceiver run hotter than it is supposed to, possibly leading to an early failure. Measuring SWR at 2.4/5 GHz requires some expensive instruments; note that the link you provided has only "calculated" SWR, not measured. Wifi doesn't involve much power, but these low cost Wifi transceivers are engineered with rather limited headroom for reflected energy and shipped with antennas that work within those limits, so if you do this you're a test pilot; there is no complaining if it lunches itself.