Just briefly: Creatine has been widely used for decades & has a safe & positive history. The physiology & dosage requirements are well explored. It is used to support overall health when sports-recovery, training & illness-recovery.
Less briefly: Creatine is for many processes in the body. Creatine is used by your mitochondria - both for energy & making androgen precursors. As a consequence, overall metabolism & especially repair & recovery depend on good creatine availability.
The above is important for recovery both from illness, training & during performance. It has been shown to improve many processes such as muscle growth (with training), recovery from strain injuries & also improved cognition.
It's estimated that dietary creatine only accounts for about 50% of needed creatine - any short-fall is made endogenously (by your body). Creatine production is not mediated by hormones so, there is little lag between stopping creatine supplementation & re-establishing base-line serum levels (blood concentration).
More specifically: There is much more to creatine than just avoiding soreness & muscle growth - creatine production is a major user of methylation enzymes. So, improving methylation capacity (by reducing the need for endogenous creatine production) helps many vital methylation activities which are very widely occurring within the body.