1: No, it only checks when you execute it. It's a one-time check. If you see more processes, maybe your bot uses forks/threads.

2: Adding it to cron means the script will be run in the intervals you define, 24x7. So if you want your bot to be checked even when you're asleep, add it. But you will have to use full paths or it will fail via cron. As long as the bot runs you won't see anything, but when it gets restarted, cron should send off an email to you (if it's configured that way) and restart it.

Or, you could find out what causes the bot to crash and fix that.