Y'know, from a certain point of view, it makes sense.
He doesn't trust mail-in voting, so that means that for a proper election, people will have to congregate at voting stations, which, let be honest, is madness in the middle of a massive epidemic.
But on the other hand, mail-in voting has been around for forever, and he still demands that schools open at the same time... Pick one, dammit.
Luckily, there is a part in the US constitution that forces Trump and Pence to resign on January 21st, regardless if elections were held or not. If that's the case, the Speaker of the House (Pelosi, I believe) will take over until proper elections can be held.