Piedmont is not one of the most exciting pieces of land on the diplomacy board. However, its position in between Marseille and Venice gives it some reason for attention in the early game. I think 8/10 games France and Italy will decide for a DMZ in Piedmont. Although this seems like the most logical move, it is not always.
The French side
France has many businesses to attend in 1901. It has to deal with both Germany and England, and ensure conquering at least one of the two Iberian supply centers, or perhaps both. Hence, there are many French players who just want a quiet southern flank and hence keep Piedmont empty.
A bounce in Piedmont is quite good for France, as it will still allow you to occupy Spain in the fall. However, it could be that your army in Marseille is already dealing with Germans in Burgundy in Spring 1901, in which case you need to settle for a DMZ.
The real adventurous and unconventional French player could decide to occupy Piedmont. You will need a few things to do this. One is to have some kind of quiet situation in the north. A successful early attack on Italy can only work if your fleet in Brest reaches Spain s.c. by fall 1901. So in 1902 you can move it to WMS directly. However, you need to ensure a DMZ in the Channel for this.
Next to a deal with England, you would prefer a German player that looks either to England or Scandinavia, you would prefer to take Belgium with just your army in Paris, but you need a deal for that with Germany.
The third condition is a deal with Austria, and I believe this is the most important one. If Austria is interested in attacking Italy you could make this work. You could even use your army in Piedmont in fall 1901 to support Trieste to Venice. Your gains can come in 1902. As Austria has quite some business to deal with in 1901, it might be difficult to convince him. However, if he already distrusts Italy, this strategy could really start to become something.
The Italian side
Italy could be a boring country to play according to some. This is one of the reasons why many Italian players focus east as the most easy to grab supply centers are in Austrian and Balkan territory.
However, what would spice things up more than a pre-emptive strike on France? This is rather difficult. Let’s imagine the Marseille army is either in Spain or in Burgundy after Spring 1901, and you have managed to occupy Piedmont. What to do next? Attack Marseille, but if the army bounces you France could end up with a build in Spain and is able to build that unit in Marseille as the s.c. is now empty. So a real attack on France can only happen if also another French neighbor is involved.
My first pick would be Germany. Appeal to the Kaiser in Berlin with the argument that central powers (Austria, Italy, Germany) have to work together and convince him of an attack on Burgundy. A combined occupation of both Burgundy and Piedmont is not lethal but at least difficult for the French forces. The downside is that France could still survive this if he ‘guesses’ right, it is also about bouncing the right army for France in fall 1901.