The writing by Cloudflare on the subject (hyperlinked here several times already, so I won't) indicates that the utility that Cloudflare sees in it is in milita

The writing by Cloudflare on the subject (hyperlinked here several times already, so I won't) indicates that the utility that Cloudflare sees in it is in militating against the sort of malicious entropy source attacks described by Bernstein. The idea is that one has a set of disparately placed entropy sources, in Cloudflare's head office (of which the lava lamps are just one) and in Cloudflare's data centre, making it hard to supplant one and simultaneously observe all of the others. I am not sure that Cloudflare is correct about this, however. It seems to me that at the point where the entropy sources are finally mixed, on the beacon machine in the datacentre, it does not matter that the lava lamps are far away, and this factor is just window dressing. The data that they generate has to arrive at the beacon machine on a serial port, Ethernet interface, or other input device, and that is the point where it can be observed/supplanted.