While the competitor adds hardware to allow chip to chip connectivity, the IKOS emulation system is a smaller and more cost-effective bench top unit used right in the lab. More parts and more connections means more things could go wrong. The cabling and connectors are simpler, neater and more efficient. There are some tasks you just cannot perform with simulation. I don't know how you would verify these kinds of complex products without emulation.
Emulation is a requirement.
The design team had to test communication at the full bandwidth, from 155 mbps down to 500 bps. This would require intensive verification, and would be too slow in simulation. Other complex characteristics of the chip also contributed to the need for emulation. Necessary tests would take days in simulation, but only minutes in emulation. Hagenmaier calculated that emulation could be as much as 10,000 times faster than simulation.