Using the comment as the item title is not really ideal for everyone. The most common convention for comments I've seen is to use an email address or username because it is useful to identify who a given public key belongs to, particularly when they're listed in authorized_keys files. That's less useful to include as a title.
I've chosen to go with the conventional key file names as the item title in 1Password. So I have titles like "id_ed25519", "id_rsa", etc. That also matches the names used when downloading the private or public key files. Though, on a related note, it would be nice if I could specify the name of the exported key file, such as "id_ed25519_personal", "id_ed25519_work" or whatever other conventions other people like to use.
It would be useful to be able to include a comment when copying or downloading the public key, so having it as a text field would be good.