In terms of OU battling... no it is not worth it. It is outclassed by Rock types such as Tyranitar and Terrakion. And it is outclassed by Bug types such as GENESECT and Scizor. And this outclass also goes to defensive capabilities.
In RU, it performs better with solid defensive stats. But the main use of it is as a Shell Smash user. No longer do you have to debate whether to use a Focus Sash or White Herb. The Sturdy ability gives it a Focus Sash, freeing you up for White Herb. With Bug type STAB hitting the Psychic types that litter RU for SE damage, as well as Rock STAB hitting the Flying, Fire, and Bug types, Crustle has a useful STAB in the tier. Access to both Spikes and Steath Rock allows it to prove useful as an entry setter.
As for ingame use, Crustle is arguably less useful, as its low Speed holds it back. Stat boosting such as Shell Smash is also a lot less useful ingame than in competitive. Crustle can still work, in BW2 it is a very useful Pokemon. But in standard BW, it is more annoying than anything else (Sturdy Dwebbles. Argh.) But if you need a Rock type and don't want to use Archeops or Carracosta (who I would prefer for ingame use) then Crustle is a good Pokemon to use.