If half the team is in office and half is remote on Slack, then the communication throughout (both useful and pointless) is much higher among the in person. Some simple examples:

1) quick clarification for a technical question - easier to turn back and ask your colleague

2) design minutiae which you remember after a 30/60min meeting is over - very easy to grab your coworkers in hallways or by watercooler and nail down

3) coming across interesting conversations among your colleagues by just being in proximity - not possible when you have to schedule a 30min chat for that

4) reading body language to know whether your colleague is stressed or relaxed or happy or sad - helps tailor your response which improves the communication

I haven't even delved into the timezone issue yet, which matters a lot even between colleagues on East vs West coast (let alone Europe or Asia). Meetings before 8:30am PT? PT people would still be waking up or dropping kids to school. 9-10am PT? Time for people in ET to have their lunch. 12-1pm PT? Lunch time for PT people. After 2:30pm PT? ET guys are already out for the day.

Whiteboards were a huge part of my daily work prior to COVID and the lack of whiteboards had a negative impact on my team. Touchscreens have not really been the same for us, it is too much overhead when all you wanted was to quickly work out an idea with someone else.

We dropped whiteboards in favour of collaborative editing of documents. People write their ideas and then comment in realtime. It took some time to get used to, but not many people miss it. Some people got reMarkable if they want to draw something and share - this is a brilliant tool, but unfortunately it doesn't support encryption, so the use is a bit limited, but to draw some flows etc is great.

I completely understand this. I think best through conversation with others involving drawing on paper or whiteboards. Without being able to do this, I can really struggle to focus ideas and plans. Online just does not work as well for this, not for me anyway.