Bitcoin is a cryptocurrency and stocks are shared by a certain company meaning owning a small portion of that company or something like that, the main difference between the two is the volatile market price of its shares. Since Bitcoin has a volatile market price and the stock market has a very slow market price and doesn't have a twenty-four-seven market, unlike Bitcoin where you could trade anytime.

If you're going to invest on eToro most of it are shares so you could buy stock out there, but they also offer Bitcoin there, I guess the best thing on their platform is you could copy something trader trades, there are a lot of traders there that has high profit, I think you could see that on there profit most of there trades meaning you know if that trader lose a trade, I have a friend who does copy trading on eToro and he didn't really need to do anything at all since he could just copy trade other traders trade.

To answer your question, If you buy like for example 1 Bitcoin it is always going to be 1 Bitcoin whenever the market price increases or drops, the value of 1 Bitcoin when converted to fiat money is the one that is gonna be affected, so for your if you buy 250$ worth of Bitcoin then the market price drops you're going to lose its value but it would not really matter if you're not going to sell because it is still 1 Bitcoin when the market price increase again the value might be back to 250$ again. So yes it doesn't have a huge difference when you buy stocks you could still keep your 1 Bitcoin even though it has zero value. Bassically you're not going to lose money unless you're going to sell your Bitcoin or your shares, as long as you buy low and sell high your going to make a profit on it.