>>54738839
>>54738781
I'm not super turntable literate, but I think one of the big reasons is that they lack counterweights. Counterweights are things in the back of your tone are (circled in red in picture) that keep the needle from being too heavy on your record. This helps preserve both the record and your needle.
Also, they might not have antiskate on them either (circled in blue), which helps keep the needle in the groove (in other words, keeps it from "skating" across the record).
I don't know anything about the sound quality of Crosley, so I can't say whether they're crap or not in that regard. But I can tell you that there are much better choices for the preservation of your needle and records.