Ottoman Empire is as relevant as the Roman Empire. The only argument why the Roman Empire gets more attention is, because it has been the basis for many ideas in the Western cultures.
Wikidata does cover more subjects and consequently it is better at making a step at representing the "sum of all knowledge". One of the people known to Wikidata is Mr Bolayır. It is certainly a challenge to type his name; I know how to copy paste it...
The Turkish language changed from the Arabic script to the Latin script in the 20th century. It does characters that are not in general use in the Western languages and consequently people do write names like Mr Bolayır differently; typically it becomes Bolayir.
Without this transliteration, people will not find Mr Bolayir when they search for him. Without his name in the Arabic script, it will be hard to link him from original sources. For all these reasons it is important to include the transliterated names people use when they search for subjects like Mr Bolayir.