You need to understand a small number of things:
1. Wallet safety and computer safety.
To play devil's advocate, this alone is sometimes too complicated a subject for many people, heh. By the time you've told them to be careful with online services designed to hold funds (which should always be one of the first things to explain to new users), make regular backups, how to store the backups securely, use a unique and strong password, not lose your password, how to keep your devices secure and malware-free, etc. many of them will have glazed over and forgotten half of what you just told them.
You're right, security can be a tough subject.
But there are also shortcuts there too, up-to-date antivirus/anti-malware/internet security is a start, don't click any links just because you've got them by e-mail (and also don't install every cr*p) is common sense and the hardware wallets are the cherry on top. See? Almost done. It's also common sense to read the manual and the hardware wallet will also tell to write down the seed and keep it super-safe.
And no,
no online wallets, starting with "online services to hold funds" usually leads to safety risks and also can lead to misunderstandings (related to fees, for example).