I mean, when you start a new VM on Hetzner (or AWS/GCP/Azure/DO/whatever) you don't memorize that address.
But cloud or not, if you setup a private network with v6 you can get a nice /48 prefix, and you give out /64 prefixes to VMs, so you'll have 48 unchanging bits to memorize (or put it into a .txt to have it near). And most of that will probably be zero anyway.
For example 2a00:1450:4001 is a /48, and 2a00:1450:4001:082b /64. Only change is "082b".
I know, it's not the same as just remembering 1.1.1.1, but most of the people working with v4 never had so simple addresses to work with. (And if we're talking about 10.0.0.0/8 and other private addresses, well, folks can continue to use them, if they want to endlessly debug NAT and static routing hacks.)
Not necessarily remembering cloud adresses, but it is fairly easy to design v4 networks. Subnet masks for example are short and understood with a brief glance at them.
If v6 would be simpler, it would also be the first choice for more local networks, hence more widespread.
