Disadvantage of constantly using clamshell mode?

[Weaselboy]

It's enough for your MacBook to charge past 80% once, and then connect it to power and it will stay past 80% forever until you discharge the battery manually by disconnecting from power. Not good for those who use a single-cable charging + display.

You don't need to disconnect from power to discharge. The macOS optimized power will do that for you. I notice when I use my MBP on battery, it usually takes a week or two for the optimized power to kick in again and set it at 80%.

 

[960design]

It's enough for your MacBook to charge past 80% once, and then connect it to power and it will stay past 80% forever until you discharge the battery manually by disconnecting from power. Not good for those who use a single-cable charging + display.

I have Apple Studio and use single cable charging. I charge to 100% for trips and return to clam shell mode where the battery charge returns back to 80% without any interference from me and without 3rd party applications: Sequoia 15.6.1

AlDente allows you to discharge the battery while being connected via a single-cable to your charging-able monitor and also provides true charge limit...

I believe this is only available via the Pro (paid) version in Clam Shell mode ( OPs title ).
Source: https://apphousekitchen.com/aldente-overview/pricing/