This is the kind of putt that golfers love. A putt that goes straight uphill means the golfer can aim directly at the center of the cup and strike it firmly. There is no "breaking" of the green to worry about, nor does the golfer have to fear going way past the hole. A simple, firm stroke should take the putter either to the hole or within 3 feet of it 95 percent of the time.
This is much trickier than putting uphill. The putter must take gravity into account. If the putt is straight downhill, meaning there are no ridges on either side of the hole, the golfer must adjust the speed of the putt. Hit it too firmly, and the putt can go 10 feet or more past the hole. On the other hand, beginners are aware of how fast a putt can roll, and they may barely tap the putt.
Many golf courses have large greens that welcome shots from the fairway. But a large green can cause problems if it has two tiers. That means two levels where the golfer's ball starts on the lower level and must go uphill before it flattens out on the top level. The golfer must putt the ball firmly enough to get it to the second level, but not so hard that it rolls off the green once it lands. This is tricky, and requires a firm touch---but not an overpowering one.