The fungo is used by a coach to hit balls for defense practice. It is lighter weight, so less fatiguing to hit ball after ball. The fungo sheds its weight above the hands. The severely tapered barrel to drops weight and maintains a high moment of inertia. While the bat would be at greater risk of breaking if used in a live batting exercise, it is safe to use in practice because there are much fewer mis-hits.
This sounds like a lot of information, but with a little practise on the coaches part, it runs quite smoothly. Two to three reps per player in the field per section is quite adequate, and with 14 men on the field, this whole routine should take about 7 minutes. It's quite snappy, and quite impressive. I had many a parent marvel to me after witnessing it - "you look like a professional team!" I wouldn't try the routine with anything less than a 14 yr old select team, but with the talent to do it right, it's fantastic.
Next, the third base fungo hits to left, who come home, third baseman cuts (again, 60' from home, about the pitchers mound). First base fungo hits to right, who throw again to second (this is where we practised cutting off doubles on balls hit into the right field corner - it's really practiseing hitting your cutoff man quickly than anything else - also the reason it's safe to do while left field goes home).
Both wooden and metal alloy (generally aluminum) bats are generally permitted in amateur baseball. Metal alloy bats are generally regarded as being capable of hitting a ball faster and farther with the same power. However, increasing numbers of "wooden bat leagues" have emerged in recent years, reflecting a trend back to wood over safety concerns and, in the case of collegiate summer baseball wood-bat leagues, to better prepare players for the professional leagues that require wood bats. Metal alloy bats can send a ball towards an unprotected pitcher's head up to 60 ft 6 in (18.44 m) away at a velocity far too high for the pitcher to get out of the way in time. Some amateur baseball organizations enforce bat manufacturing and testing standards which attempt to limit maximum ball speed for wood and non-wood bats.
Once in a while, veteran managers revive it. The Giants took infield occasionally in 2008 and 2013 under Bruce Bochy, and Jim Leyland instituted infield drills before batting practice late in his tenure in Detroit. Molitor, for one, misses it. He took infield even as a designated hitter late in his career because he hated sitting around for almost two hours waiting to play.
Fungo bats are typically only used by coaches, to consistently place grounders and pop flies to their fielders for practice purposes. And with a fungo bat in their hands, some coaches can pull off wicked accuracy – as one story goes, the late California Angels player and coach Jimmie Reese once shot an 82 on an 18-hole golf course using nothing but a putter and a fungo bat.