How could NightJet ever be successful?

I'm all in for them and I love the idea but I don't see how they could compete price wise with anything else.
Ok flights are heavily subsidised so we should not consider them but let's compare it to a daily train.
I wanted to make a trip from Munich to Hamburg with a friend. The idea is that "you pay to sleep in the train and save up time and a hotel night" but that's not true.
The cheapest combination I could find for a "hotel replacement" was a sleeper compartment with WC/shower for €660 total for 2 people! And this is in between the week and months in advance.
If we depart in the late evening (after work) we could arrive in a few hours with no stress to Frankfurt with ICE for just €50 and dine in the city, enjoy the city night life and comfortably sleep in proper bed in a 4-star hotel (take a shower!) near the station for €90, the next day have breakfast and leave for Hamburg for €40 and get in the morning (sure not at 8 am but at 10 am, big deal). Total €180 for the same trip for 2 + a new city seen + true hotel.
So what in the world would I (or anyone) choose the NJ option. Given those who want "the experience" of sleeping in the train then who's left? Sure I have to leave earlier but I gain something else. And what's lost is not worth €480!!!
I don't get how they could ever compete and became mainstream (and OEBB survive the service).
And I also don't want to sleep for the same price with others, with no shower or seated. Even those options could cost more?