I was going to start this post with two videos of Giannis, that show exactly why he's so great, but I couldn't figure out how to embed them, but here's one, and here's the other. In the first, Giannis uses his massive wingspan to get up and block the big Miroslav Raduljika, in the second, Giannis reaches with his long arm, and gets the steal, then goes 3/4 of the court for the dunk in only three dribbles. At the combine, though they weren't official measurements, Giannis measured in at 6'-9" with a 7'3", then in December was measured at 6'-10" with a 7'-4" wingspan, and before the World Cup, was measured at 6'-11", and his wingspan is probably now higher. Giannis is massive and that is why analysts are convinced that he is the next big thing in NBA basketball, but fantasy wise, he might not be as good as we think he is.
In his rookie year, Giannis struggled, a lot, averaging only ten points, 6.4 rebounds and 2.8 assists per 36 minutes, which while not very good, was around what was expected from the raw nineteen year-old, with no experience playing high level basketball. Despite the Bucks terrible play, Giannis wasn't given big minutes or usage, he played only 25 minutes a game, and playing 99% of his minutes at either of the two forward positions, which is why he had a usage percentage of 15%, much lower then it will be with the current point guard experiment.
The point guard experiment, that's what makes Giannis hard to predict. At the World Cup the Greeks mostly used Antetokounmpo as point guard in transition only, because his quick speed, long legs, and longer dribbles, make him perfect to lead a fast break, but in the half court game, he was often put in the corner, where his three point percentage is less then 7%, far below league average, but there's a reason why only 13% of his threes were shot from the corners, and he was actually above average from top of the key, and right wing.
Another problem with the point guard experiment is turnovers. Due to the constant handling of the ball, point guard is a the toughest position to play in basketball and it comes with a lot of turnovers. Giannis didn't turn the ball over often last season, only 2.3 per 36 minutes, and 18% of them came from offensive fouls, something that will surely decrease next season, but he's made up for it with more bad passes and lost balls, and averaged 3.5 turnovers during this preseason.
Steals and blocks, that's where Giannis helps most. Basketball-Reference projects the Greek Freak to average 1.2 steals and blocks per 36 next season, and this preseason, he's averaged 1.17 and 1.75 respectively. For perspective, last season, only eleven players who averaged above 20 minutes per game had those numbers, and only four played small forward, that's a big bonus to fantasy owners, especially if your team lacks those two stats.
The Bucks suck, they're tanking anyways, and have nothing to lose letting Antetokounmpo loose at point guard, and seeing what happens. Not only that, but the Bucks now have Jason Kidd, a hall of fame point guard, as head coach and Kidd will be able to mentor Giannis as the season goes on. In my fantasy draft, I reached for Giannis, and took him the tenth round of an eight team league, because I wanted him, and I knew my league mates wanted him just as much, but I think that because of his shooting guard eligibility, and high potential, Giannis is a good pick, just not as high as I took him.