Any laptop ought to support running batteryless directly off of the charging port
Even if the battery goes old and replacements become scarce, it can still be something
There's a good reason why some phones don't: there are some GSM (2G iirc) radios that rely on a battery to even out some pretty high spikes in current draw when transmitting.
This exact reason probably doesn't apply to laptops, but I wouldn't be surprised if some similar reason did. Obviously one could always add a sufficiently beefy capacitor, but that costs \shruggie{}.
