It's true but if you know which addresses have bitcoins, you can simply backup private keys of those addresses if you want. Surely it's more easily and even more safely to backup a wallet mnemonic seed words because it's easy to do such wallet backup and I don't see big reasons for don't do this and why a Bitcoin user must skip mnemonic seed words backup to use specific private key backups.
Since you already know that backing up private keys individually is less convenient and riskier (more prone to typos) than backing up the wallet seed, then I honestly don’t think it’s wise to suggest doing so, especially when we know that many newbies might read your post.