Those are pretty good arguments you can use to convince your boss to start using your calendar software! So why hasn't he switched? I see some possibilities:

- No-one has pointed out these shortcomings to your boss.

- You have, but he is stubborn and refuses to see the downsides even though they are obvious to everyone else.

- You have, but you're overstating the downsides and the current setup actually works well enough as it is.