Very useful, foam rollers, balls, the end of my bed, fingers ,thumbs. I’ll use anything to get the pressure applied.
I would say stretching only required when muscles shorten due to lack of use, thru injury or laziness !
Rollers and balls etc can be used any time you get tight muscles loose.
I put my leg bone through my pelvis, shattering it, requiring a 5-6 hr op to rebuild. 8 months off work, getting physio the whole time. Broke 2 ribs and my collar bone too. Twas coming off my road bike at approx 25mph, hitting a wall.
Physio introduced me to loosening the knots and trigger points.
Three years later almost back to full fitness, still get the roller out for my legs and hip though.