Containerization is very different from virtualization in terms of how it works and how it affects performance. In general, the performance of Docker containers is very close the the performance of non-containerized processes. So that in itself is not expected to significantly impact Elasticsearch's performance.
You should remember though that ECE does constrain Elasticsearch containers in terms of CPU time, memory capacity, disk capacity and I/O throughput. This helps ECE isolate cluster nodes running on the same host from one another, mitigating the noisy-neighbor effect. A native process is typically not constrained this way, so while it may run faster due to not being constrained, it will also consume more resources from the host OS at the expense of other processes.