Shiba is reliable for long term but that doesn't make shiba a better bitcoin intact they aren't even close, shiba isn't fully decentralized and bitcoin is, shiba started as a meme coin and now it's going metaverse, the best challenger is doge coin not bitcoin
I don't know whether buying shiba at this time for long term investment is too late or not because the price of shiba has experienced a very significant price increase in the near future. I personally am not too sure about long term investment in shiba because in my opinion all meme coins are not suitable for long term investment and more suitable for short term investment or day trading.
Quite hard to really go into meme coin because their lifespan is questionable. What if the dev team behind this abandon in no time or disappear once he got what he wants? Then, your tokens will be worthless. So if in case you will buy some, make sure it is the amount that you can very well afford to lose. Because investing on this type of project is unreliable. You can never compare it with btc though.