I spend 4 years in a infantry platoon where we carried around a 60mm mortar tube with no bipod. Totally useless and inaccurate but we carried it, why, because infantry platoons in WW2 carried a 50mm mortar and it was our doctrine. PIAT was useless compared to bazooka, it was more complicated, cost more to make, had less range, less killing power. It's one redeeming feature was the ability to be fired from inside a house like the modern Armburst or Eryx. The reality is that we could have been armed with bazooka at less cost without denying any to the Yanks and the PIAT production could have been used for something more useful. We were issued it because it was "BRITISH". A fetish we are finally starting to kick the habit of.
Was the PIAT the all singing, all dancing wonder weapon of the day? No, there was better available but with that said, it did get the job done when it had to.
http://steel-chariots.22web.org/panther.htm