I cannot find any real reason why you should spend your bitcoins in order to shop online.
In my opinion, Bitcoin has a bigger value than the one right now so it is not worthy spending them for shopping. It is better to keep them in your wallet and consider it as your investment. If you want to buy something online use a stablecoin...
Why not? as an investor, we can also spend, we can do both actually, so it's not wasting your bitcoin because as an investor, you'll ensure that you will not touch your investment until a certain time will arrive or it will hit your target.
Correct mate and also for Bitcoin to be adopted and starts to be use worldwide there must be a supply and demand but since the mindset of everyone is to Hold bitcoin and wait until the value goes up but not thinking that Bitcoin must be circulated to prove that it has really a value.
If you have fiat now and you like to shop online using bitcoin, then you covert it, that's what people do, if they spend bitcoin it doesn't mean they don't value it now and its future.
Absolutely ,Just like traveling around the world and using your Bitcoin if there is a chance than bringing your Pouch/wallet with fiat and sometimes needed to convert your dollar first for the local currency before enjoying the place,while if the Bitcoin is available in that country you can just use direct payment from your Online wallet to the establishment or restaurant .