This is a great question - I don't think many women today would like to be in the same situation as Portia! However, as Bassanio mentions to Antonio in Act I scene 1 about the lady "richly left", it is clear that the inheritance that Portia has received can be viewed as much as a curse as a blessing. Portia herself in Act I scene 2 certainly bemoans her situation to Nerissa, complaining that by her father's will she is not able to choose her husband - only if they successfully pick the right casket with her picture in it will they gain her hand in marriage. Note what she says about her longing to be able to choose:
O, me, the word "choose"! I may neither choose who I would nor refuse who I dislike; so is the will of a living daughter curbed by the will of a dead father. Is it not hard, Nerissa, that I cannot choose one nor refuse none?
Portia here points to the irony of her situation - her will is curtailed by the will of her "dead" father, although he is long gone and she is still alive. She also points out the lack of freedom she has - for not being able to choose also means she is not able to refuse.
However, in response to her grumblings, it is Nerissa who actually answers your question by explaining the wisdom of Portia's father's conditions:
Your father was ever virtuous, and holy men at their death have good inspirations; therefore the lottery that he hath devised in these three chests of gold, silver, and lead, whereof who chooses his meaning chooses you, will no doubt never be chosen by any rightly but one who you shall rightly love.
Nerissa sums up the wisdom of Portia's father's actions. As a "virtuous" man, he can be trusted so that the "lottery" that he created will only allow somebody who is suitable and worthy for his daughter's hand to succeed. Herein lies the wisdom - Portia's father has designed a test to weed out the suitable from the unsuitable, ensuring that the person who triumphs is of a suitable moral character for his daughter.
When this matter was recently broached, it brought to mind a lyric by the rock band CHEAP TRICK: "mommy's allright, daddy's allright, they just seem a little weird." For while requiring suitors to go to church and swear an oath or two seems "virtuous," we learn that Bassanio has visited Belmont before and his talk of shooting a second arrow and mention of a "secret pilgrimage"(1.1) might suggest the possibility that Portia's father did not like Bassanio and laid down the conditions to allow others a chance to win Portia. In Professor Bevington's intro we also find the conditions present "an ancient parable stressing the need for choosing by true substance rather than by outward show."