Starting from Firmware 1.0.25 we can Login to YouTube (Premium) thanks to an unofficial YouTube Client (https://smartyoutubetv.github.io/)
But, if you want more Google Apps or even use an already existing InApp Purchases from an other Android devices, an Vendor/Products needs the Google GMS Certification (Android – Google Mobile Services)
Long Story Short:
Lets bring this demand to Googles attention, because since over one year they don’t respond to Philips Inquiries send f.e. via Google Mobile Services - Contact
Vote AND comment in the official Google Issue / Feature-Request Forum: