If the connection gets loose, it will act like a resistor, heat up like the heating element. The connector metal has some spring to it. Once heated and cooled depending on how good the connection is, it can lose its temper or springiness, and when it expands, not contract again so it no longer makes a good connection. That's why the crimper tool is more science than art...hard to determine if you got a proper crimp. Often, it really doesn't matter much. But, on high current and things like heating elements when exposed to extremes in temp, it can make a big difference. Time will tell. The proper crimping tool takes this all into account, and uses the best shape and compression to form a reliable, long-lasting, low resistance connection. SOmetimes, this is overkill; sometimes, it is essential.