Blockchain.com/explorer is one of the old explorers that does not want to upgrade to the modern types, the feerate on the site is in sat/byte while many new explorer represent the feerate in sat/vbyte while some indicate both which are appropriate. I will advice you to use better explorers like blockchair.com.
Once a transaction is initiated, the user will receive an automatically-generated transaction hash from blockchain and can use it to look up details of the payment and whether it was successful. This will help you avoid falling for flash coin scams and others.
It depends, in this regard, if replace-by-fee is not enabled and the bitcoin is sent with high fee in a way the transaction can not later be dropped from mempool. If replace-by-fee is enabled, the sender can trick the receiver thinking he has sent the coin but of which not yet confirmed, the sender can double-spend the transaction back into another address on his wallet or into another address of his choice.
On the image, the 0.00107 btc is yet to be confirmed by the blockchain network and needs at least four confirmation.
On noncustodial wallets, only a single (1) confirmation is needed, you may be confused with the exchange you are using that will make it mandatory that certain numbers of confirmation is needed. But in design, only 1 confirmation is needed.
Blockchain explorers are useful when you want to explore the blockchain as a database in a UI for some general stuff, not to keep track of your own transactions. To do that you must use your own wallet, a wallet that is either built on top of your full node (eg. bitcoin core) and can tell you precisely the status of your transaction (in mempool, double spent, abandoned, low/high fee,...) or a SPV wallet that can tell you the same things with a good level of confidence.
This is just correct, why checking blockchain explorer. I have used like three wallets now, all are noncustodial and SPV, only one confirmation needed, and well indicated on wallet if a transaction is confirmed or not, I think this is enough. Full client wallets like Bitcoin Core will be good for full tracking which will make such blockchain explorers not useful, while SPV wallet can indicate a transaction that is confirmed or not yet confirmed, this will be advisable for privacy.
But there are exceptional cases when someone using SPV wallets will not have any option than to make use of blockchain explorer, a good example is during escrow service, Mr A sent bitcoin to escrow service provider ( Mr B), while Mr C will send fiat. In this case, Mr A will provide txid so that the seller Mr C can check this on explorer, while Mr C will send the receipt of the fiat sent to escrow provider to Mr A for transparency that they have actually sent the funds to escrow. There are still many other reasons blockchain explorer can be very important for transparency.
I have not seen SPV wallets that indicates if incoming transaction is replace-by-fee or not, some organizations can accept incoming bitcoin transactions that replace-by-fee is not enabled, with this, if not having full client wallet, the organization will have to make use of blockchain explorer to track the transaction.
