No one 'needs' Polemaster. Polemaster came along at a time before Sharpcap's PA tool and is (Polemaster) built as a vehicle to sell their camera. With Sharpcap you can use virtually any webcam that will fit into a 1.25" eyepiece tube. A cheap webcam can work, but looking to the future, an ASI camera might be a good investment simply because of the flexibility it gives for many uses: guide camera, video camera, long exposure subs, and PA tool as well. Have a look at the ZWO website, or browse through the ZWO section of Bintel's website to get a view of what is available:
https://www.bintel.com.au/product-ca...g/zwo-cameras/
For what you want, at this stage, you do not need a cooled camera, so something like an ASI120 might be fine.
I am sure you will get all sorts of opinions here, and with the large Polemaster user base out there, they will encourage you to join them, but imho as a tool it is a bad investment given the Sharpcap tool availability now.
Btw, you do not need a guide scope to use Sharpcap PA, your camera can simply plug into the focuser of your scope, provided your scope can provide a 2 degree field of view it will be fine.