He chose a symbolic random date that has close to zero scientific data behind it, but, that's Trump.
Not going to argue about the reasons, we know we can't stay forever under lockdown, you can't quarantine 300 million for that long and expect when they come out everything to be fine, restarting an economy half or 3/4 shut down for that long will take a lot longer...

But the whole "easter" thing makes nonsense.
Unfortunately, some areas of the country have not yet seen the real numbers of the spread, even if you quarantine them now, there is no time till easter to eradicate the virus. And when people will come out of it and feel safe and travel much more than before, what we need is one case for a repeat.

A 2-3 months lockdown will not be possible, I'm out of self-isolation myself right now after a hell of two weeks and now that I'm free...well, I'm free to go to the supermarket and thank you god to take my kid out for a walk so he can unleash some of that infinite energy he has, but if this goes for more than 2 months I won't make it out of this sane.  Nor will my company with just the work from home scheme.

Till easter is too early, till May is too much, everything between is a gamble. But we're not talking about just money but also human lives.
No matter how you look at it, there is no decision that will be good for everyone.