I have seen several posts on either the idea wall or content requests for German cards and can only echo this desire from a personal selfish perspective as my children are raised bilingual and so far all German content we hear on Yoto is either the German Ladybird card (which my son loves) or our own cards where we record books for.
However, in addition to pleasing the already bilingual customer bass with any case:
The Yoto is far superior to the Toni box: the mini, the app, using android auto... - just to name a few. The fact you can use your own phone to manage the Yoto as well as the kids using their own cards is a massive USP that will grant you success in a market that may be very established with Toni, with clever marketing.
Yoto can be a strong contender in any German speaking market and if not already done so, you should consider exploring some research into the market release.
I myself have several friends in Germany with Tonis who are amazed by my Yoto Mini alone actually and even more the digital aspects it comes with. They would choose it over Toni if it came with German content.
The benefit to existing customers: German cards naturally. Not just German specific stories that some people have mentioned in card requests (Benjamin BlĂĽmchen, Bibi Blocksberg) but also German versions of classics such as Julia Donaldson stories, the hungry caterpillar, fairy tales (Grimm especially) and so on. So far we have to go to Spotify for this but even here not all of them are available (but exist)
Thanks for reading :)