Do good power cords have to be stiff?

I've gone mostly to DIY power cords which are quite unwieldy but, back in the day, I found the offerings from Wolff and 6Sons Audio to be both very good and quite flexible.  6Sons Audio Golden Eagle is the best power cord I've heard.  Neither come up very often but usually are a bargain at used prices.

Good power cables are often solid core and hence stiff by nature: to wit: Nordost, Acoustic Revive et al…

Just look at some of the Puritan videos on youtube.  The epitome of flexibility, combined with great performance.

Cardas power cords (lower level, which I what I know) seem flexible compared to most (as do lower level Nordost, though I haven’t handled those myself0

+1 Puritan.. almost feels like water