The metric is: "The number of unique addresses that appeared for the first time in a transaction of the native coin [sic] in the network." They're not excludin

The metric is: "The number of unique addresses that appeared for the first time in a transaction of the native coin [sic] in the network." They're not excluding old, never-reused addresses, so the number of addresses is always increasing as every transaction adds more. What they tweeted was that this rate of increase has itself increased by about 20%. Since blocks have been full during this period, this means the difference lies in the type of the transaction. If the current transactions are more of a fan-out (pay multiple parties) and less consolidation (sweeping payments made to the same institution), then that makes sense. And indeed, right now there is a larger than usual outflow from exchanges. Maybe people are getting nervous about holding increasingly more valuable bitcoin on exchanges and are pulling their funds off? That alone could explain a 20% increase in this meaningless "address count" metric.