It's the double-tap and hold then drag gesture that is the problem.  The Pixelbook touchpad demands that you double-tap and hold then pause for a fraction of a second before starting to drag.

It may only be a few hundredths of a second but when working at speed, and coming from a Windows environment where touchpads are more forgiving and allow you to start your drag the instant that the second tap is made (or even a fraction before, inferring the start point of the drag from the location of the first tap) it's _very_ frustrating that my Pixelbook misses so many double-tap-and-drag-to-select gestures.

FWIW, I've been using a Mac for the past 10 years, and am struggling to adapt to the less forgiving PixelBook

I didn't realize that I should pause after the second tap before moving my finger - I'm able to use the feature a lot more often now with this small change to my behavior.

But I agree that I shouldn't need to change my habits.

It's only a small pause, I've found -- may 1/10th of a second -- but it's a distinct pause and if I don't do it, I miss; very annoying.

With practise, I feel like I've got so I can shorten the pause to the absolute minimum, but still I have the occasional miss which disrupts workflow and just makes the Pixelbook feel a lot less 'usable' than it should.

This seems to be fixed on the dev channel as of today.  There was a touchpad firmware update a week or so ago, that didn't seem to make much difference.  Then another touchpad firmware update today.  And after reboot it seems I can tap and drag with no noticeable delay required after the second tap before the beginning of the drag. :-)