Hi Praneeth,
Hope you are doing well!
Apart from the points made in the earlier replies, I would ask you to check/consider any reporting requirements that may be driving the need for the capability. Some organizations, prefer creating BAU projects as it provides the ability to further breakdown the larger BAU bucket into identifiable chunks of work. Although that wouldn't be the case for true non-project work such as training, meetings, time-off, etc....for which Other Work would still be your best bet (And I am not even getting into a very old debate of using indirect time vs other work ).
Also, if the BAU activities are same, why do you need to have different ones per practice? If there is a reporting need, wouldn't you be able to pull that from the associated resource record? But then what do I know of your requirements
Thanks,
Debroop