The Bahn automats were accepting strip cards last fall when I was in Germany.
The Bahn website (German language side) has an "Automatentour" under Services > Vor der Reise > Ihre Wege zur Fahrkarte > DB Automaten. The website's tour is in German, but the actual automat can display in English (touch the British flag). The opening screen shows four square touchpads. The touchpad on the upper-right, labeled Gesamtes Angebot in German, is where you touch if you want to purchase a QdLT or SWT. That gives you eight new touchpads in two column. The second pad down on the right is for Gruppenkarten (group tickets, QdLT and SWT). Regional tickets, like the Bayern-Ticket are on the top LH pad. The part of the tour on paying with a credit card specifically shows to insert the card with the strip down and to the right, so I assume they use it. And, of course, the automats take cash.
I don't see anything on this thread or on her other two threads about the day of the week or number of people. The QdLT (Quer-durchs-Land-Ticket) is valid on workdays (44€ 1st person, 8€ each extra person to 5 total). On Sat, Sun, and holidays you can use the Schönes-Wochenende-Ticket for 44€ total for 1 to 5 people. Same limitation of regional trains, but no 9 AM restriction.
For Savings Fare tickets, the first person is x9€; each additional person up to 5 total is x0€ (i.e., 49€ for the first, 89€ for two [49€ + 40€], 129€ for three, etc). Children under 15 are free with their parents if declared when booking the ticket.