I played auto bet on freebitco.in back few years ago with small budget of around 30.000 satoshis. I used Martingdale system and rised funds to around 40.000 satoshis after that I got losing streak and lost almost all the funds. To be honest I would not be confortable to gamble bigger sum.
Entrusting an auto bet bot with a huge amount of money to gamble can be a very big mistake. An bot doesn't have human instincts and experience. It's possible to have some wins using this system but the chances of making profit in the long run would be very small. It's wise of you not to try out huge amounts of money because it might end up being a disaster. It's preferable to continue maintaining smaller sums of money
If the person would try to give the auto bet not with huge amount, they can keep a close watch on it to see what is happening. If you don't watch it, maybe you left it to go to bed, you might wakeup to see that your account balance is at zero dollar. Using the not should just be on a close attention and not in your absence. I will not use the bot if It can not bring profit, I just prefer manual betting.
After all I also prefer manual betting, but that doesn't mean I never use autobet. I use it sometimes and with small amounts while playing dice and plinko. Also I never let it unsupervised and I wouldn't recommend anyone to let it run without any supervision.