There is nothing wrong about using the website though, but Asuspawer09 only suggest the bitcoin wallet that is generally used by everyone because they have a more flexible features that is vouched from the majority of the forum members here. Again, you are freely to use the bitcoin wallets suggested from the website.
I think Coinbase is a good place to store bitcoin I also use Coinbase to secure my bitcoin. It maintains the balance of many reliable places and accounts
No. Do not exchange the "security" of your funds over "reliability" especially if you are storing a large sum of money. In fact, some of non-custodial wallet offers the same or much more "reliability" than using the coinbase or any other custodial wallet.
However, if we keep the private key of the wallet safe, then other wallets are reliable Stay away from new services and Coinbase many secure wallets.
It is ironic though, you are telling people to keep your private key safe but you do not use non-custodial wallet. I am just telling this for you to be aware that securing your money is the first essential thing when dealing with your bitcoin or any other crypto.