Because they are inferior, Alpha's are possible to eat your machine up and spit it out.
While beta's have had a little more testing and bug fixing.. and as such is less likely to do verious nasty things to your computer.
Though you should note there is a chance beta's could still do so.
Before you install Alpha's and Beta's think carefully !
(I have spent more than a few hours in dos fixing my baby)
Because of alpha's and beta's.. but i have not done so in quite sometime.
Yes it is thrilling.. even when your pc goes wahh wahh oops! boom
Anything less than a final release are inferior.. that's why it was given a Alpha or beta status..
A bug here maybe something not been implemented as yet or maybe the program is hungery and likes to eat pc's because of the said bug.