My father has had his Twike for seven years now. I wouldn't recommend it, the suspension is not up to snuff, even just for daily commute. Getting repairs done is a major difficulty as there are very little parts or mechanics readily available. He also had to sue the Twike company when they tried to defraud us w.r.t. warranty and insure documents. The legal issues have been on-going and they stalled the repair of the Twike for about a year.
Simply the cost of it (25.000 euros debut price?) seems to defeat the purpose. The weight being closer by far to a small car than an electric bike doesn't help either. I suppose people who need specifically that much room in their vehicle and/or live somewhere very cold could see utility but given the maintenance issues you mention I'm not surprised it isn't a big seller.
My father now commutes by electric bicycle.