Reading a book about K2 by Ed Viesturs where he shares the joke that bivouac is the French word for mistake. By that definition I’ve only bivvied once in a bag lent to me by a fellow rider, and twice in my own bag and all three times were awful.
If it isn’t an emergency it’s camping not a bivouac ;-)
On the only ultra race I did I slept in Airbnbs and one campsite as my daily contingency planning was much better than I ever expected. I am actually quite proud that I kept within Dutch law and was very safe and got 4 hours sleep every night. Not that getting my eyes licked by a wild boar didn’t sound appealing (yes it happened to someone). And I only camped because I had to justify the extra weight of my emergency camping kit which otherwise wouldn’t have been unpacked.
Your mileage may vary.