Currently, Bitcoin Testnet3 is reaching $0.3 steadily. I think that before the end of this year we will see it above the dollar.
In other words, the market cap is very low. Looking at current page of
https://coinmarketcap.com/?page=12 and testnet3 price ($0.3), testnet3 would take position #1176.
It lacks the key property of a currency.
It has more currency-like properties than most of the shitcoins still

It also has been around than almost all shitcoin.
Currently, Bitcoin Testnet3 is reaching $0.3 steadily. I think that before the end of this year we will see it above the dollar.
Every now and then there is a scam running in the altcoin world where they swap some shittoken for tbtc and that pumps it to about 600 satoshi (again with the same low volume) and then it comes back down.
You are overthinking it in my opinion.
And it comes under various name, such as airdrop and testing. Related thread,
Why High Demand for Bitcoin Testnet Coins?.