Yes. Suppose you gain possession of 20 STEEM each worth 20 cents at the time. The blockchain paid you $4 of taxable earned income. If you sell it five years later, say, at a price of $10 a piece, you get $200 and the price you acquired them at was $4, which makes a capital gain of $196. So you must pay earned income tax on the $4 and five years later capital gains tax on the $196.

Finland considers income earned in virtual currencies on online gaming or "mostly recreational" platforms to be taxable only when they are cashed out into fiat, goods or services or virtual currencies external to the platform. What this means is that users of platforms like Second Life or Roblox can earn virtual currencies internal to the platform without their earnings being taxable until they cash out.

A quote from the guidance:

There are numerous – mostly recreational – games and programs on the internet that use their own currencies (such as gold, gemstones or coins) and earnings from which do not count as lottery winnings. In this guidance, all online games and programs are referred to as games regardless of the actual nature of the program in question.

Many online games give players (users of the program) the chance to earn currency by their actions in the game. Some games also allow the game's internal currency to be converted to real money or virtual currency. Players can also earn by selling attributes that they have developed in the game, goods that they have purchased in the game or the game's internal currency to other players for official currency, virtual currency or other benefits of monetary value.

Pursuant to Section 110 of the Income Tax Act, income is deemed to have been earned during the tax year in which it has been withdrawn, deposited into the taxpayer's account or made available to the taxpayer otherwise. In this guidance, these kinds of games and any virtual currency associated with the games are considered one and the same. This is why any virtual income from games is only considered to have been earned pursuant to Section 110 of the Income Tax Act when the player cashes out from the game. Taxation on income cashed out from online games is triggered when the player converts the game's internal currency or other benefit associated with the game to external virtual currency, real money or other assets of monetary value. Income from online games is valued and taxed according to the fair value of the asset received in return for the game's internal currency when the player cashes out from the game.

https://www.vero.fi/en/detailed-guidance/guidance/48411/taxation-of-virtual-currencies/