[Bluebottle]

Bulky earbuds can transmit noise from the helmet into your ear by being in contact with both.
Maybe the wireless buds have improved in size/shape - it’s a long time since I tried them.

I use earplugs and helmet speakers for comms and GPS ( rather than music).

 

[Bluebottle]

To be clear, I only had trouble with bulky wireless buds, not the wired ones.
I used wired Senneiser ruggedised buds for years with no problem until getting Bluetooth built into my last two helmets

 

[Bluebottle]

Whereas several fifths pretty much guarantees self incrimination

 

[Bluebottle]

My Nolan helmet has the room for the Nolan Bluetooth intercom (more than 200€). I bought on Amazon a chinese bluetooth helmet stereo headset for 16€...

The Nolan unit is very expensive - but it’s very good (battery lasts several days, good speakers and intercom range is further than high end units fellow riders use).
I have the NCom B5l with brake light in my N104 Absolute helmet. But I agree the price was a bit eye watering.