We definitely should take benefits from them as long as it’s possible. Of course, it is difficult to find not a scam for long term holding, personally I do in the following way:
First of all, I investigate the idea of the altcoin’s project and its docs, then I overview the team members and I also check if any “whales” are going to invest in it. Secondly, I find out about marketing campaigns and social media. Also I get know if there is a big community and there are many people who trust it and want to invest.