However, Bitcoin is facing many challenges in terms of reliability and practicality in use.
What are these reliability and practical challenges, BTC is very easy to use and is a reliable currency if the spender controls the private keys to their address, there's no mass adoption yet, but BTC is already used almost globally in different numbers depending on the country.
Bitcoin's transaction speed is limited,
Layer two systems like the Lightning network is a solution to the problem of scalability. By the way BTC's transaction speed may not be the fastest, but it is one of the most immutable, irreversible and safest, there are some networks in which transactions are confirmed faster, but those transactions can still be reversed after a long time. In the BTC network once there is 3 transaction confirmations, the funds can no longer be reversed, and i think i will take this level of speed and security, rather than faster speed and less security.
and the consensus among miners is also unstable.
There is no instability in the BTC consensus mechanism.
In addition, the use of Bitcoin faces many difficulties in converting to traditional currencies and the legal regulations are very vague in some countries.
It is easy to convert from BTC to traditional currencies and back, either using centralized or p2p exchanges. If BTC is not banned in your country, then no worries about the vague legal regulations there, the government are confused on how they can control a decentralized currency, but they cannot.