It’s the precedent it creates and image it projects to. We’ve always sold our best players in the PL era, we however always made sure we got a fair price and then some to compensate, we were always obstinate and “don’t want to sell“. We never sold two of our best players in one window, not to my memory unless it really suited us.
Now it seems systemically the Spurs and Chelsea’s of this world can come and say - let’s just throw them 50 mill and take their best players - be great bench options. What’s more sad is some are more then happy to grab the penny’s that fall from the CL top table.
If we do this, we are admitting we are on the same level of the Palaces of this world - probably worse as they had the gumption of realising what they had in say a Zaha.