It's NOT about you
Unless you are running for public office to hold the power to create and remove laws, your personally held beliefs are not an issue.
They are an issue once you are running for public office.
It says little of a person's convictions, their closely held values, if you do not act in their defense.
Once you are in office, those values take on a very different color, you are empowered to act on them.
Doesn't mean you would vote to overthrow Roe v Wade but you may be persuaded to compromise, you as a politician, get something "X" and in return vote with others of like mind to restrict access to reproductive healthcare options for minors or cut funding to PP just a little. Nothing earthshaking on it own maybe but just one more cut in the "death by a thousand cuts" to women's rights.
That is why it matters.
Be it women's rights, LGBT rights or immigration or the imbalance of our justice system toward people of color.
Power.
The power to act on those beliefs, for good or bad, changes everything.