If you buy a day pass, you don't need to buy a €7.5 OV-chipkaart but will get a disposable chip-card instead. You do need to check in and check out like a regular OV-chipkaart each time you use public transports. According to the same website, those passes are not valid on trains.
I haven't checked in the last few weeks but until recently, it was still possible to buy traditional paper train tickets in Schiphol and Amsterdam CS (which are among the handful of train stations in the country where you can use the self-service ticket machines with foreign credit cards) so you don't need an OV-chipkaart for that either.
As far as I know, when chip-cards will finally be made mandatory on trains (it was supposed to come for a long time, not sure about the exact status), you will be able to buy disposable single-trip chip-cards to go through the “portals” in the stations. It will probably be the best option for visitors because taking the train with a regular OV-chipkaart requires at least €20 credit when checking in, even if the trip costs much less than that.
This means that after a trip back to the airport from the center of Amsterdam with a regular OV-chipkaart you would have at least €23.5 tied up in the card (that's €7.5 to buy the card and €20 minimum check-in credit minus the €4 fare). I don't know if it's possible to get the money back but that's a hassle in any case.