Exactly.
If you’re only ever going to be using the pulse sensor, then unless you can persuade the shop to sell you a case, you’ll need either the emonPi p.c.b. (which gives you the analogue front end which you don’t want, in addition to the pulse input which you do); or you’ll need to connect the optical pulse sensor to the GPIO of your RPi and write a service or a Python script to count pulses, calibrate the count in kWh and send that value into emonCMS. Here’s how to do that: Directly connecting to Optical Pulse Counter with RPi? - #2 by pb66
(And you’ll need to download and set up emonCMS on your RPi).