One of the problems with cryptocurrencies is scaleability. Most cryptocurrencies are derived from the Bitcoin codebase and thus have a "block size limit". This limit has become a big issue in the Bitcoin community and led to fierce discussions. Monero doesn't suffer from this block size debate, because it has a dynamic block size limit. This limit is automatically recalculated regularly based on a look-back window. A penalty system prevents out of control growth of the block size. Another issue with most cryptocurrencies is the development of a fee market. This issue is somewhat linked to the block size debate: the narrative is that when you limit the block size, a fee market will eventually develop. But this claim is highly debatable. When the transaction fees are supposed to be the main incentive for miners to secure the blockchain, it is possible the current consensus model will not be sustainable. At the moment, miners still act as they are expected: they mine on the longest chain. When they don't do that, they risk losing the block reward. But when that block reward becomes small compared to the mining fees, it's possible miners will have an incentive to not mine on the longest chain and start a fork trying to "steal" high transaction fees which were included in the latest blocks. Therefore, monero implements a "permanent block reward". The block reward will never drop below 0.3 XMR, making monero a disinflationary currency: the inflation will be roughly 1% in 2022 and go down forever, but the nominal inflation will stay at 0.3 XMR per minute. This means that there will always be an incentive for miners to mine monero and thus keeping the blockchain secure, with or without a fee market.