Batteries degrade over time, regardless of cycles.
Every now and then we'll see a thread with someone's 2015 Mac has 30 cycles because it was always on the charger and the battery has degraded to 90%. No ****.
If you store a battery, it will degrade over time.
If you use a battery, it will degrade over time.
If you only use your Mac on a charger, it's even worse, because you're "storing" a battery at full capacity in 40-50C heat.
If you use it every now and then, it will degrade but a bit less.
Batteries are consumables.