I ask all of the photographers that work for me to use a second card as backup.
Two months ago, one of my photographers did not do so and I lost a full day of images from that shooters arena due to a corrupted card, so yes, I feel a second card is essential.
We all know that memory cards can fail, but exactly what camera model and card type/brand that corrupted card was?
I have had a couple of Compact Flash and SD cards fail. I had plenty of warning for that CF card around 2004/2005. I had corrupted images that traced back to a particular Lexar SD card, when Lexar was a top brand a decade ago when it was owned by Micron.
On the other hand, I have been using XQD since my D5 in 2016, and I use dual XQD cards. I transitioned to CFexpress Type B around 2020/2021. With the Z9, I shoot 8K video that fills a 325G, 512G card. So far I haven't had any failures. My cards are probably not old enough yet, and I tend to use ProGrade Cobalt and Delkin Black only.
If I have to use one CFexpress B card, I would stick with a top brand and take older cards out of circulation. E.g. some wedding photographers, in addition to using dual cards in the backup mode, replace all of their cards for wedding photography after every season, so that they do not use very old cards that are more prone to eventual failure.