Altcoins have always been the way when you want to make more money than just investing in BTC/ETH. But it comes with a much higher risk.
Those coins are the same. When you are investing in bitcoin when it was around 7k last year and you have been making 5x ROI for your investment and the same thing can be applied into the altcoin too when you are investing into the legit coins and that will give you possibility to get huge ROI from your investment.
Altcoin gives an alternative way for people who can't afford to trade or invest a lot in bitcoin. It's just like an alternative solution for low - medium tier of traders.
No. They are not the same. Bitcoin is going up, because of an increase in adoption and mainstream acceptability. But the same can't be said about most of the altcoins, as they haven't experienced the same. They remain in the same position they were a couple of years back. The prices are going up because of some spill over influence from the Bitcoin rally. As such, none of the alts have shown any improvement in the adoption or acceptability aspects.