Of course, the larger your bitcoin investment, the more important it becomes to aim towards storing your bitcoin yourself rather than keeping them on custodial services, and the threshold regarding how much bitcoin anyone is willing to keep with custodial services is going to depend on individual circumstances, yet at the same, time I would think that most people should be striving to protect their own interest in regards to not keeping too many coins with custodial services.... because there are a variety of ways in which custodians can lock you out of your coins.. but if you also are not very responsible person, then you have to learn how to be responsible if you are going to make sure that you guard your private keys once you do start to use a private wallet. Guarding keys with backups and don't overly complicated it and don't leave your keys vulnerable, since anyone who gets your keys has abilities to get your coins and transactions are not reversible once they move the coins to their own keys or to the keys of someone else or cash them out.
If you read first message of this thread then it's one way to understand how storing Bitcoins in your own decentralized wallet is different then storing in custodian wallet. If you have your Bitcoins on some custodian exchange like Binance and you left your coins for more then 6 months without logging into your account then it's very likely that once you get back to access your account it might be blocked due to different reasons like non provision of facial ID etc. There are chances that your account might be active but then they might have deducted some of your bitcoins as part of some maintenance charges. These issues re very common when you store your coins on some exchange.
It's only your own wallet that will give you full coin whether you come back after one year, ten year or even more.
So learning about bitcoin wallets is not a prerequisite to getting started in bitcoin, even though learning about wallets is an important and powerful thing.. .At the same time, some people might be challenged in their abilities to learn about bitcoin wallets and to put their learning into practice without screwing up.
Bitcoin has lot much stuff to learn not just the wallet. See the "Development & Technical Discussion" section and one can find there is lot much to learn in bitcoin like ECDLP, secp256k1, digital signatures and more. If one is interested in learning the underlying technologies then he is welcome to do that along with investing in Bitcoin. Since it will be fun to see how your money is stored and secured on Bitcoin Blockchain.