Use of host.TrafficKeyPublic[0:32] as AES-GCM Key

[s0metea]

In migrate.go and util.go, the following approach is used for symmetric encryption:

encrypted, encryptErr = encryptAESGCM(host.TrafficKeyPublic[0:32], zipped)

Here, host.TrafficKeyPublic[0:32] is used as the encryption key.

Questions:
1. Is this intentional?
2. Shouldn’t the encryption key be randomly generated and then encrypted asymmetrically using TrafficKeyPublic?
3. What is the rationale behind this design choice?

If this is by design, can you clarify the reasoning and security implications?