TPC-C (circa 1992) models the OLTP "old school" application, which looks like a wholesale distributor with a small number of warehouses, full of inventory serving a large number of outlets. In this context, it measures "transactions per minute" (tpmC). It involves the architecture of the old school, where DRAM is very scarce and, as such, it relies heavily on the IO drive.
TPC-E is a modern OLTP application that simulates an exchange brokerage service and uses a much more complex simulated world caused by stock price fluctuations and emulates a chaotic "outside world" of customers placing market orders, limit orders and stop-limit orders, TPC- E involves a modern IT architecture where DRAM and computing resources are more plentiful and therefore independent of storage performance.
TPC-H is an OLAP workload that measures query analytics in a data warehouse context.
In a nutshell, TPC-E is good for OLTP, TPC-H for OLAP and TPC-C are mostly outdated.