What usually doesn't come with a PPI is the tech looking you in the eye and saying, "Yes, buy this car."
The information you get out of a PPI will help you decide what the car will cost. It's up to you to decide whether or not it's worth the cost.
The reason you're asking is probably because you know there are things that a PPI will not/cannot reveal such as the amount of wear inside the engine and the condition of the solder inside the electronic modules.
Specific to the M104 engine in a 300CE, you'll want records to tell you how long ago the head gasket was replaced. If not recently, you could be in for the cost of replacing the head gasket in the next 20,000 miles.
I don't know if that car was part of the batch that had a faulty engine wiring harness. It's way past manufacturer warranty coverage despite the low miles so that's another potentially costly situation to consider in the absence of records.
On the other hand, none of my cars came with records and I haven't had any nasty surprises that complete records would have helped me avoid.