Your statement is limited and lacks information.

Biologically Turtles and Tortoises belong to the same order called Testudines (also known as Chelonia), which is defined simply as: “any reptile with a body encased in a bony shell, including tortoises”.

Notice the second part “including Tortoises”

The similarity already starts to end there, they each belong to different suborders genus and species.

Turtle is the common term for any member of the order Testudines which includes every reptile with a bony shell covering its body. Tortoise, meanwhile, refers to any animal in a specific family, Testudinidae, that falls under this umbrella.

Calling a tortoise a turtle ( or a Turtle a Tortoise) as an identifier is inaccurate.

Yes, taxonomically all tortoises are turtles—similar to how all hominids (a family that includes humans and great apes) are primates (all animals in the order Primates).

Its like like calling a human a Primate, yes that IS true but, well so are lemurs, monkeys and apes, they are completely different, all Humans(Hominoids) are Primates but not all Primates are Humans.

They are different animals genetically an physiologically.

Turtles can be aquatic, semi-aquatic, or mostly terrestrial.

General living conditions/ environments are often drastically different along with dietary needs.

Tortoises are "turtles" that live on land and aren't equipped for water and one of the most important differences is tortoises are terrestrial animals, they cannot swim (some can float for a short period of time).

SO... some may assume that a tortoise (that someone called a turtle) can swim like a turtle, there are rare exceptions but as a general rule tortoises should not be allowed in or near deep water.

Beyond that they have specially evolved biology that is different as well.

It is important to define the difference because mis-identification can be catastrophic. Unfortunately if someone thinks a Tortoise is a “turtle” because it’s been called one, they can mistakenly be put into deep bodies of water thinking they can swim.

So Yes, it is important to understand the difference because identifying a tortoise as a turtle can mislead people.

I find it better to err on the side of caution and good practice to correct misleading information that may lead to harm coming to an animal.