SRRC filter -- filter span tradeoffs
Lower rolloff means less excess-bandwidth and therefore longer time span.
That is, you will need a longer filter to accurately reproduce the ideal RRC filter response (increases implementation complexity)
Longer filter means more accurate RRC filter and potentially lower ISI at the receiver side (depends on your target SNR)
Longer filter means less noise out of band transmitted (infinite length filter would have zero power outside symbol-rate*(1+rolloff)


In practice, due to the above constraints, RRC filters are usually not designed by just truncating the ideal RRC impulse response. Either you multiply the impulse response with a window function or you directly optimize the filter coefficients for error and rejection.