Apparently, if Musk manages to delay any possible close past next April, his existing financing promises from other sources will expire. Those financiers could then choose not to promise the same financing, in the new environment, which would be one of the established "outs" for the original acquisition contract.

So enough delay is a roundabout way for Musk to get what he wants. Both Twitter & the courts understand this, though, so are unlikely to entertain delay-for-delay's-sake.