It does totally eliminate variance, but they also take that into account and correct for it when looking at final outcomes usually. Right now the bot is up by something like 800K over 60K (out of 120K) hands. If that rate continues, it will win by around 1.6M or 400K per human. The blinds are 50/100, so that would equate to roughly 33 millibets (thousandths of a big blind per hand). That isn't too far off from standard win rates in bot vs. bot tournaments [1].
I'd say it's likely that the results of this tournament will be a statistically significant win for the bot.
[1] http://www.computerpokercompetition.org/downloads/competitio...
Typical winrates in human vs human are between 1-5ptbb/100 where 1ptbb = two big blinds. At 1ptbb the variance is pretty big and north of 1million hands are probably necessary to establish an edge, whereas at 5ptbb the variance is much smaller and 100k hands are usually enough to converge to the expected value