The fans themselves don’t need to be unplugged often, only the usb plug to the powerbank has a lot of cycles.

The 3m friction tape is interesting, but tbh I think the simple 2.5mm headphone jack would be a bit easier to do and to replace in case it breaks and likely a tiny bit more reliable as I can buy it pre-done with built in stress relief against bending and it can also twist since it’s around to reduce any twisting related stress.

The snaps look interesting for me but not for conducting electricity but for potentially holding the cables. I see the brass/tin plated snaps a bit to be risky as they could potentially short out the powerbank when the fabric flexes which I really want to avoid. While I don’t have a cheapo powerbank, so it has short protection, I’d want to avoid testing that involuntarily. (At least I’m afraid it might do that) (Note, while the current which I use is low, the powerbank can deliver the standard 5v 2A, so a short could carry 2A in the worst case)

The magnetic ones from rosenberg look interesting, but they are again quite large compared to the 2.5mm headphone jacks or even the 5.5mm 2.5mm barrel plugs.