On the positive side, the emergence of alternative cryptocurrencies helped to increase overall public interest in the concept of cryptocurrency and blockchain technology. By offering alternative options to Bitcoin, altcoins helped to broaden the appeal of the cryptocurrency space and attract new users who may not have been interested in Bitcoin specifically.
I hardly find a positive side to bitcoin because most of all these altcoins had been created to make corrections to bitcoin. Some being developed under the POS and we all know they end up not being able to correct bitcoin and follow its trend which actually defeats it purpose. When you see a new altcoin trending then it is certainly for people who looking for a quick rich scheme.
In the area of adoption I think Altcoins has actually drive people away from cryptocurrency due to the growing number of scam coins. You find it hard to convince someone who has less knowledge about crypto and has loose funds to this shit coins that bitcoin is by far different to this Alticoins.
Also for those who have sufficient knowledge about cryptocurrency, altcoin doesn’t provide competition to bitcoin