Really the total number of throws is all that matters.
For scoring purposes you are correct. But to help a player understand whom the course was designed for, published Par can be good to know. There are other good and valid reasons why par is important too.
A course with thoughtful design has
challenge built in for the target audience/player to achieve par,
excitement & satisfaction designed in for birdies and
disappointment & frustration built in for bogeys or worse. Playing courses that are targeted at ones skill level will produce those
emotions....and those emotions are a huge part of why many people (the ones with at least one competitive gene in their bodies) get addicted to DG.
Now, if I play a course that is too short for me birdies are routine/boring, pars are disappointing and bogeys have nothing to do with the course punishing me and everything to do with my poor performance. Likewise, courses that are too long for me are impossible to birdie (so I miss out on that excitement) and have pars that are typically routine (shortish upshot every time). So the only emotion left is the disappointment & frustration of screwing up. To me, that is not a lot of fun since there is no upside and only downside in trying to do my best.
Of course in real life, most courses seem to try to offer a little to everyone which makes only half the holes (at best) good, rewarding and fun for any given person. But still, you can get a pretty good idea of whom the course was designed for by looking at the par listed on the signs.