in T/O phase you have surely enough fuel in each tank, therefore noo need to open a cross feed valve. why not keeping them segregated? Moreover the cross feed valve is there only for abnormal situations. What will happen if by playing open/close it remain struck open? If later you have a fuel leak situation you are in trouble.
Again, such generic commentary doesn't work, because the practices and procedures which are appropriate vary with the airplane, and the nature of the operation in progress at any given time.
Having crossfeeds open may be a very valid approach for the same reasons you've described...one doesn't want to risk it being stuck later, and for outboard tanks which hold a lesser quantity, having the crossfeed open and able to accept fuel from larger tanks for balance is a much better option than having it stay stuck closed and being unable to feed from other tanks.
What's opened when, and where, and how and why really depends on the airplane and what's being done with that airplane. Sometimes it's appropriate, sometimes not. One simply cannot make a generic statement about cross feed and have it be applicable on a general basis.