Testing new exchanges is probably not necessary when the competitive chances of new offerings are relatively low, the exchange seems to have confirmed its owners as major exchanges such as Binance, Bittrex, Okex and several others. Priority and satisfaction always lie on these big exchanges, with new exchanges, what we can see is a little special feature and airdrop they create, UNI is a prime example of the benefits of observing the advent of new exchanges but as you say, new exchanges have too many fraud risks, pay attention to events and rewards, do not put money into participation
I think if you are not going to do something major, you could just stick with the big names and keep trading there, but if you are not going to do something like that and if you are going to end up trading on a place like a very low level exchange because they have that coin you own and you want to sell it and that's it, it's going to be hard.
I once used one exchange to claim idena, idena wasn't on many exchanges (haven't checked if they are listed in good places now) and in that horrible horrible exchange, there wasn't many coins, since I cashed out like 50 bucks worth of idena, I didn't want to use bitcoin or ethereum since it would be super high, I was asked to pay like 40 bucks just on cost, so I didn't do that.
The only coin I have ever heard of was dogecoin, seriously aside from bitcoin, ethereum and doge there was all coins with under 5k dollar volume per day, it was horrible and they charged terrible withdraw costs as well even for doge. In the end I got my money out of it. There are those type of situations where people do end up using those exchanges.