Yes.

If you always direct-play, the only bitrate you can use is original.

If you ever need to watch on a slow connections using a lower bitrate, that will require transcoding.

Or if you want subtitles but the player doesn't support them. Then jellyfin will need to burn them into the stream.

Good point, and I agree - after reading all the responses, I'm leaning toward spending the few extra bucks so that I don't have to fret all the potential scenarios that might require transcoding.

Or is it better to save a few bucks now and save it for next year when something new comes out that is faster anyway. Maybe there is a new codec that matters in 3 years but nothing today supports: so either way you are forced to replace your server.

There is no right answer, you are taking your chances when planning for the future. There are many computers more than 10 years old still working just fine in the world, and it is possible that whatever you buy today will be as well. We get enough press releases that we can predict what will happen next year close enough, but in 5 years we have much less information. There is no way to know if saving money is a good choice today or not. I can come up with scenarios either way.

Look at power use. Often last generation hardware uses more power for the things you do today and so the few dollars you save today are made up with in the power bill over the next couple years. (though if you use that new hardware to do something the old couldn't do the new will use more power!)

If there is only a few dollars difference in price go for the best. However when there are hundreds or even thousands of dollars it becomes a harder decision.