Depends. I recently was in that situation and it was easier and more cost-effective to just print them.
I recently bought some Lego Star Wars sets and printed out some Display stands for them but the connection between the stands and the model was expected to be a 2x4 Lego plate. I didn’t have those plates at hand so I looked online and found it from the official Lego site.
The individual “Plate 2x4” would cost 0.14EUR each. Since I needed 3 this would be 0.42EUR. But the mailing costs would be over 9EUR.
So ordering 3 of those Lego pieces would cost me almost 10 bucks. I just printed them out which worked well, they were a bit tight fit but are still holding.
But I wouldn’t necessarily say that this is a replacement for actual Lego pieces. As a quick alternative that you can’t see or that has less interaction with other pieces (doesn’t need to fit correctly on all sides) then I think this can work.
DnDBeyond is a tool that you can use to play your campaign. It also has and offers the rule books but also campaign books digitally for your account.
So no, when you rely exclusively on the hardcopy books that you have to play the campaign, then this wouldn’t really matter much to you. However, when they decide that you cannot use DnDBeyond to keep track of your campaign and characters and so on with a previous version then you would either need to convert to those new rules or not use DnDBeyond anymore.