Sounds right to me. raiisak, players can receive points using the Points for Playing field on the Game tab. This awards points on a per-tournament basis.
On the Stats tab, when computing statistics over a number of tournaments, the Tournament Score and Overall Score formulas are available for you to compute other values - not necessarily points. Tournament Score can be used just like Points for Playing. With Points for Playing, you could create a different formula to award points for each tournament, since each tournament has its own Points for Playing field. Or you could use the same formula. Whatever you like. But if you wanted to change that formula, you'd have to go to each tournament and change each formula. With Tournament Score, the resulting value is available only when you compute statistics. And you only have one formula, so it applies to all tournaments. However, if you decide to change it, you just change it in one place and recompute statistics, since there's only one Tournament Score formula per profile, and it is the same across all tournaments when computing statistics.
The Tournament Score formula computes a value for each tournament. The Overall Score formulas each compute a single value for each player. It could be used in many ways, but mostly you can think of it as a way to combine values from the Tournament Score formula.
As an example, say you allow players to accumulate points for basic things like buying into the tournament, and purchasing add-ons or rebuys. This would be ideal for a club or restaurant that wants to award players when they spend money in a tournament. You could use the Points for Playing formula, or just the basic buy-in, rebuy, and add-on "Points" fields. If you also want to rank players over a series of tournaments based on how they perform, you could then use the Tournament Score formula, using a formula like you've mentioned: log((n + 1) / r). Those Tournament Score values are computed for each player, for each tournament. Ultimately they need to be combined in some way to produce a rank-like value for each player. So you could set one of the Overall Score formulas to do just that: (1-exp(-average(scores))) * 100. (These are the formulas for the default Stats Profile, for anyone reading along.)