OK @SuePJ, here is my Janet and John description of a Firestick.
Cards on the table, I am no computer techie but I have blundered through enough installations of my own and some friend’s Firesticks to get a usable understanding of these modern miracles.
Like you, I also have a smart TV. It has French and UK satellite boxes connected. It can load and run its own and apps and we have a Firestick. We use the Firestick to watch media content more than any other device. Everything is controlled by a single simple remote control button (which is also duplicated on our ‘phones). We tend to only use “on demand” services to watch what we want when we want. We rarely watch live broadcast (e.g. UK satellite transmissions)
They are plastic rectilinear boxes with a HDMI plug on the end which plug directly into your HDMI port on your TV (exactly the way you do with your laptop). They are small, about the size of a breadknife handle (the internet loves weird units of measurement!) and need a USB type power supply.
They are basically a small but powerful computer which runs various apps, for example BBC iPlayer, ITVX, More 4, 5 Player, U, Netflix, YouTube. These apps are loaded from the Amazon App store. It is important to understand that each country has its own app store to download apps relevant to that country. As far as I can tell, you do need an Amazon account in that country to be able to access its content. You also have to tell Amazon which particular country you purchase your digital media from (even if most of it is free). You can only select one country. So in our case it is UK. I had already done this years ago to be able to download Kindle books from UK. This does not affect regular purchases on your normal French Amazon account.
There is a facility to download unofficial apps called “sideloading” but that has not interested me.
So, it is going to work very similarly to your laptop. You select your app. If it is a geolocated app like iPlayer you will also need a VPN app and need to set it to a location that works for that particular app. It is a matter of trial and error to find the best location and after a few weeks or months it may well change. The same thing applies on your laptop. Some apps like YouTube do not need a VPN.
So why would you buy a Firestick rather than continually plug in your laptop? Well mostly it is a matter of convenience and quality. Once you have set up your Firestick you can forget about it. The video and sound quality is much better than you will get from the laptop and the Firestick uses better streaming software so you get fewer periods of buffering (although they can still occur sometimes)
If you are going to buy one and are not in a hurry they often crop up quite cheaply during sales occasions.