Are the random numbers generated by php functions mt_rand, rand, etc. predictable? ?

Are the random numbers generated by php functions mt_rand, rand, etc. predictable? ?

Additional question:
Because I recently wanted to build a one-dollar treasure hunt function, I saw on the Internet: For example, the one-dollar treasure hunt plug-in in ecshop uses data related to old lottery and users to calculate luck. number.

But if a function like mb_rand is random enough (that is, almost impossible to predict), then why not use a random function like mb_rand to generate lucky numbers? ? Instead, we have to go through a lot of trouble to retrieve data and perform various calculations? ?

If I use the mb_rand function to generate lucky numbers, is it fair? (I’m afraid that the random numbers generated by this random function will be predicted, and then I meet some advanced players who randomly fiddle with some numbers and predict them. Then That would be unfair)? ?