Hi
the question is contrary, in that most use one or the other, or a mix of both for their portfolio's.
because if you use parkingcrew, then you are attempting to collect revenue on the traffic and possibly get inquiries on your domain, from that traffic, using that platform.
if you use a typical landing page with no advertisements, you may get inquires, but then you loose the potential to earn any revenue from those visitors.
note that all pay per click services have ability for you to receive sales inquires thru a link on your parked page.
the ability to earn parking revenue from your domains, can afford you the income to pay renewal fees on those and possibly other domains in your portfolio.
that, in turn, puts you in a position of comfort, where you can wait for the right buyer, because your domains are paying for themselves.
imo….