The answer is, it depends!
As you show a $ price, I'm assuming you're in the US and that your guest if any would have access for a separate fee ($25?) each time.
My view on PP is that is a useful extra. I should say that my PP membership is included in my UK American Express platinum card fee for about the same price (£225), so I do not pay extra for my use of PP lounges. UK Amex platinum also gives me access to some other lounges including Virgin Atlantic, bmi British Midland and Eurostar. Not sure if these are included in US Amex platinum.
Lounges in the US include Delta, Northwest, US, TWA and America West.
One limitation: PP have no lounge access in Australia or New Zealand.
Hope this helps.