When uploading a sketch to an esp8266, isn't that the same as "flashing firmware"?

Question

I thought that I read that using a PC running the Arduino IDE to "upload a sketch" to an esp8266 overwrites the original firmware (with the AT commands), and is actually "flashing the firmware" each time a "sketch" is uploaded. If I have that right, then why does the esp8266 WiFi still visible in available connections? There must be some code instructing the esp8266 to do this, but where is it? My sketch was simply the hello blinky thing and contained no #include statements. Where have I slipped?

Answer 1

Uploading a "sketch" is indeed "flashing firmware".

why does the esp8266 WiFi still visible in available connections?

I'm not sure what you mean by that.

• user37116: Sorry, poor grammar. Should have been "...then why IS the esp8266 still visible..." And by "available connections" I mean the list of access points within range of the WiFi enabled device being used. Like on my PC there's a WiFi icon in the system tray which I click on when looking to join a network. I don't know what that menu list is called. Anyway I'm puzzled as to how my esp8266 would still show up on that list even after the original AT commands firmware was overwritten by my little "sketch". I assume there must be some code somewhere making that happen, and I'm curious to understand.