Soft tissue therapist here. To clarify, sports massage tends to be a bit of a buzz word for deep tissue techniques. A good therapist (and clinically focused therapists) will have a lot of further techniques in their tool kit including a number of stretching techniques that cannot be done alone and are very effective for tissue length and general mobility. Especially in the case of muscular injuries such as strains allowing them to stretch segments of muscle without aggravating damaged tissues. As well as neuromuscular techniques to attempt to tackle trigger points and overall general improvements to tissue function and scar tissue reduction.
Sports massage is definitely beneficial, but it is also only a complimentary therapy and the best results come in conjunction to using the foam roller and stretching outside the sessions. When people come into the clinic, depending on the condition of their soft tissues they tend to have the first early sessions quite frequently and then they just reach a level of maintenance and require it significantly less often to maintain.
The best effects come in conjunction with stretching, foam rolling and careful programming to avoid imbalance.