It is short term if you decide to sell. Bitcoin can be whatever you like, and if you sell too much too soon, you might have wished that you had treated your investment into bitcoin as long term instead of short term.
Let's take a longer term example. Let's say that someone came into bitcoin in 2014 and spent a couple of years accumulating bitcoin, so maybe he accumulated around 50 BTC at around $500 each. So his total investment is $25k. So when the BTC price shot up to $2,000, he could not resist, and he sold all of his BTC, and so he ended up selling them for $100k, and so he has around $75k in profits... that is pretty good, right? He is still not doing as good as the longer term investor who still has the 50 BTC, and maybe the longer term investor has more BTC and his average cost per BTC is more than $500 per BTC.. we can imagine a lot of scenarios, and bitcoin has tended to be a good investment to hold onto for the long term, even if you might get enough BTC and you might want to shave off some profits along the way, you can still consider your investment as something that you mostly hold onto rather than converting into dollars and then ending up with dollars or some other inferior investment or maybe consumption good that you would be better off to have more BTC at a later price, even if your cost per BTC might end up being much higher.
Selling our bitcoin too early would surely lead to regrets especially when we are never able to buy back bitcoin at that same price we did as when we bought it, many person's are talking about taking profits even some early investors that I know that I started with and I'm like how many bitcoins have you accumulated that you feel you are on the right for taking profits, the truth is many of them came in for the profits and never had any intention of staying or holding bitcoin for a longer term.
At times it is very possible that bitcoin would never go back to former prices and those who were opportunited to have some early bitcoin that they got at a price if 25-30k earlier this year and decides to sell this bull run might never be able to see the likes of bitcoin in those price range ever again and would have to get it at a even higher price, to me if you haven't accumulated up to 5 years you should not be think of selling or taking profits the plan is to allow as much compounding value effect on your portfolio as possible.