81 Euros to Select A Seat in Premium Economy?!

I just booked a $3k RT from MUC to SFO through United and was surprised when I went to select a seat through the Lufthansa app that any seat selection would be €81. What a racket. I was excited to try out the new Alegris product and paid $300 more to fly LH vs United, but now considering a switch back to United metal. Is Alegris worth it?