I agree that it is a good thing to move our funds from exchange to our own wallet but it would be expensive if we do it every time we buy cryptocurrency. Like when we are withdrawing BTC from Binance, it was said that the current withdrawal fee of Binance is around 0.000068 BTC which is around a little above $4. Imagine if you DCA BTC for $10 worth each time you buy, you will only receive a little less than $6 if you decide to withdraw the funds each time of transaction. That would be a huge lost on your part. I think to maximize the efficiency of saving funds, one must have a threshold on how much he has on his exchange fund before he withdraws his holding to his own wallet.
So I think, while it's best to get our funds out of the exchange asap, it would be a huge loss for people who frequently buy BTC in a small amount. Besides, as the earlier reply stated, Bitcoin transactions is not anonymous. Bitcoin is not a privacy coin, being decentralized does not mean it can hide your privacy. @OP if you wanted to have full privacy of your coins, I think Bitcoin will fail you.
especially the newbies are mostly not aware that they can move their bitcoin to a more convenient and secured networks such as decentralized wallets for self custodial
This is wrong, most people feel centralized exchange is more convenient, that's why they purchase Bitcoin using
DCEX over P2P or DEX.
corrected this one for you