would you guys consider exchanges that have their own tokens/coins (e.g. kucoin with their kucoin shares, binance with their binance coin) to be generally more trusted/credible, or less, or it doesn't matter much? especially when their own coins contribute the largest trading volume, i always wonder is the volume made-up or inflated (because we never know).
No, I don't think just because an exchange has it's own coin it means it is more trustworthy or legitimate, look at Bittrex as an example they do not have their own coin and is one of the best exchanges.
I can understand why some exchanges have their own currency but it doesn't bear relation to the trustworthiness of the site.