Fingers crossed these songs were chosen as a one off for a one off acoustic show.
That would be my guess, although I hope it went well enough to persuade BF to repeat the format, which should better suit his mature voice.
The only problem is that smaller venues means fewer seats, which would almost certainly mean even higher ticket prices.
I hope BF takes the same approach to the gigs with strings in Amsterdam and Antwerp in June; there are songs which would suit that treatment far better than those in the regular set list and the Dublin shows a couple of years ago were a missed opportunity.