I don't know why you must do that but in my role as a manager, on our cost plus and time and material contracts we have to collect costs by hours worked on specific tasks in order to know how much to bill our customers. We collect these costs by employees reporting their worked hours against contract line items. I have a fiduciary responsibility to validate those hours reported and I have to electronically approve those hours. If I don't check in some manner that the hours reported are accurate then I am not doing my job. Just taking my employee's word for it is not enough. A check in e-mail to HR would not be enough for me. I actually check with my team daily and know who is working where, when and on what. We have an unlimited time off policy, but you must request time off or if it is spur of the moment, you much let us know, an IM or text is sufficient. Failure to notify the team of an absence is poor job performance. Failure to attend schedule meetings is poor job performance. Being inaccessible to the team when working is poor job performance. If you need focus time to work on a difficult task, schedule it and notify the team. If you can't attend a requested meeting decline the meeting or suggest an alternate time. Attendance is important in the office or virtual. Lack of attendance is a strong indicator of poor performance. If a designer has to wait days to get a simple answer from a stress analyst because the analyst does not answer messages during normal (core) working hours, the analyst is hurting the team's productivity. One thing that working in a common office location does facilitate is communication. If you need something from someone and they aren't answering messages, you can just walk to their desk and see what is up.