Even though I had disabled all 'restore' applications features, macos sometimes decides to 'start' browsers BEFORE logging in after a restart AND those start auto-playing audio from whatever was paused before the reboot (or many days before).
Since then I went rather deep disabling that feature, but I never trusted it.
Bluetooth and wireless radios stay on for a longer while because to keep everything connected if you are moving from room to room at home or at work, also it's made possible because all radios are higher end models with their independent processors.
When you close the lid, macOS directly sleeps, shutting down fans in ~10 seconds if you have them, reaching S3 (Suspend to RAM) state. Radios stay alive a little longer to keep any BT/Wireless connections to speed things up if you're just moving places, then they go dark as well.
If you enabled PowerNap on charging, your laptop will wake up briefly after some time (Every hour or so) after you plug it in, check mails if Apple Mail is open, check for any system updates, and sleep if there's none after fetching the mails (It'll download the updates if there are any, IIRC). If you have setup Time Machine, and the drive is available (locally or via network), PowerNap will wake the system and take a backup every 24 hours, making sure that your backups are always up to date.
Per factory settings, PowerNap on battery is off, so it'll sleep without any disturbance up to a month or so, and will hibernate when the battery is low.
So, yes, the laptop sleeps as soon as you close the lid. But wakes up periodically to make sure that everything is fetched and ready (if it's connected to power, by default).
BTW, There's an actual method called Power Nap involving short naps to recharge. It's not an Apple naming gimmick [0].