At the end of the day, it's fundamentally a blank check for management to misbehave -- to misspend money, pursue pet projects rather than real business goals, and have nobody to tell them no.
There is nothing inherently short-term about the stock market -- this is a myth that keeps getting repeated but has zero substance. Short-term changes in supply and demand add changes to prices, but it's not like anything's 10x off of the value a company is expected to produce -- the net present value of future cash flows.
But if you prevent people from selling, then you're preventing the market from holding a company accountable when its management messes up.