One thing to note with the new progressive taxi instructions is the fact that you need to send “expect progressive taxi” before you send any progressive taxi instructions.
2.2.2 — Before it’s used, controllers should send ‘Expect Progressive Taxi Instructions’ to the aircraft in question (although this may not always be possible) […]
In order to get ahead of this, a good way to be proactive is by sending the ‘expect progressive taxi” command after telling the aircraft to pushback, if you know you will need to send progressive taxi instructions to that aircraft.
If you were to wait till you needed to send them taxi instructions, you’d need to send potentially in some cases, three commands. ‘Expect progressive taxi’, ‘Taxi to runway X’ and a progressive taxi instruction ‘turn left next taxiway’, for example. By sending it in the pushback you cut those commands down to only two, the taxi instruction ‘taxi to runway x’ and the eventual progressive taxi instructions ‘turn left next taxiway’. This speeds up the process.
Use progressive taxi sparingly, but if it’s needed, be proactive not reactive.
Resources: 2.2.2 of the Infinite Flight ATC Manual