They're absolutely not, though.
Someone who came up 100 times with runners in scoring position and got a hit 80 times is significantly more valuable than someone who came up 400 times with runners in scoring position and only got a hit 100 of those times. The fact that the first player may only have 60 RBIs and the second player may have 175 RBIs - and people valuing the 2nd player over the 1st - is the issue with RBIs, whereas BA with RISP would show that the first player had an 0.800 BA with RISP while the 2nd player had a 0.200 BA with RISP.
How do you know who is more valuable by simply looking BA/RISP? Do you know how many were on base? How many outs? The result of the hit?
BA/RISP is a poor stat to assign value to any player. There are stats that do a much better job in relaying run expectancy and run creation.