I look a pass prices this way: the 7-day Global Pass costs $383. To that you must add the cost of mandatory seat reservations where required ( certainly for the TGV from Paris to Interlaken). I do not know what those are, ut for the sake of illustration will just round up the total to $400. That means your cost on travel days must average out to $57 each for the pass to be cost-effective.
If you look at the cost of regular (“point to point) tickets bought 4 months ahead to get the best price, you will see that only one of your travel days will exceed $57; the rest will be under that amount, so the average cost will be under $400, including seat reservations.
For example, here is what I found on SBB.CH and bahn.de for the discounted prices for tickets bought online today for a random date in June ( June 28):
Paris to Interlaken Ost on the train with a single change in BSel, CHF 68 in 2d class, including seat reservation for the TGV
Interlaken Ost to Freiburg (via Basel), CHF 40,15
Freiburg to Colmar, €43 ( but there is probably a cheaper option if this is a one-day return trip. and Inagree with Sam that since you are renting a car from Freiburg you may as well use it for the daytrip to Colmar).
Munich tomSalzburg, €12,90.
If you take Sam’s suggestion on the rental car for Colmar ( which you should), and look at how inexpensive thickets can be if purchased about 4 months in advance*, and consider that the Eurailmpass will not help you with the mountain lifts and trains in Switzerland, you will likely conclude that the Eurail pass is not a good value.
Yes there is a learning curve involved in buying the individual tickets, but it is not difficult, and actually can be fun. At least I think it is. And there is some learning involved in using a Global Pass as well—note that you were not aware of the mandatory seat reservations for some trains. Those are not always easy to figure out—we see a lot of questions here on how to get the seat reservations on French and German trains. Also note that the number of seat reservations available to pass holders may be limited, especially on the French TGV.
*Speaking of limitations, the advance-purchase discount tickets on international journeys are also limited in number. Also note that they are generally non-refundable and may be non-changeable. So less flexibility.