Bidoofdude is correct. Just expanding on his point...

Hasbro and Takara(TOMY) have an agreement not to interfere with each other's markets without permission. Thus TakaraTOMY will always market their toys at their market unless there's a previous agreement with Hasbro on joint collaborations, but even then each company is responsible for distributing and servicing their toys in their own respective market.
e.g. TakaraTOMY will not service a POTP or Studio Series toy purchased in a Hasbro market.

English is a foreign and exotic language to people in Japan, much like Latin and other Romance languages are to people in Anglophone countries. For example, how many English speakers care that the name Ultra Magnus is nonsensical, since "Ultra" is FEMININE? "Volcanicus" is a completely rubbish and made-up word, the word "volcano" comes from the Latin word "Volcanus," which means "Vulcan," the Roman god of forging weapons (known as Hephaestos to the Greeks). The Romans had no word for "volcano." One of the reasons why Pompeii wasn't evacuated in the days leading to Vesuvius' eruption was because the Romans had never seen an eruption before. And by the time it happened, it was too late to evacuate and the Pompeiians perished. A Roman fleet commanded by Pliny the Elder was even lost as they attempted a rescue by sailing into the ash cloud, which would have instantly killed them... cos ya know, volcano ash is freaking hot (but apparently Chris Pratt can survive going through it in Jurassic World The Fallen Kingdom! ).

So yeah, the presence of English text on Japanese packaging is completely irrelevant to the idea that it's also intended for overseas release. It's purely there to make it look more exotic. Hasbro once did the same thing with their release of Beast Machines Magmatron. This packaging has Japanese text on it despite being targeted towards the Anglophone market, not the Japanese market. But the Japanese text makes it look more exotic! Same with Hasbro MP boxes which prominently feature the word 傑作 (kessaku) on their boxes, which is the Japanese word for "masterpiece," but NOT the Japanese word for "Masterpiece." The Japanese use the word 傑作 in describing things like a piece of art - a literal masterpiece. As far as the Japanese product line is concerned, it is only ever called マスターピース (Masutaapiisu), which is the Japanese approximation of the word "masterpiece." And 傑作 even appeared on toys that were never released in Japan, like Masterpiece Acid Storm.

And if you think this sounds weird, remember that the very fact that 50% of words in Modern English are of Latin-French origin is pretty much because people living in Norman-England just wanted to make their English sound more cool and exotic but mixing in French words. Yeah. English already had existing words, but even peasants started using French words because it just sounded cooler.
Wanna eat some cow? Nah, let's call it "beef."
Sheep? Veal.
Care for a drink? Let's say "beverage."
Want to see our list? We'll call it a "menu."
Have a seat on this stool? Let's call it a "chair."
Did you get jumped this morning? Let's call it "assault."
Is he friend or foe? Or shall we say "ally" or "enemy"?
Shall we eat? Why not "consume"?
Learning knowledge, or studying science?
Will Prince Harry be giving a warm welcome or a "cordial reception"?
Are we Shapeshifter Gatherers? Let's say, "Transformers Collectors."

And we still use straight out French and Latin words/terms for all sorts of things.
e.g.
and so on = et cetera (etc)
good thing = bonus
already seen = déjà vu
of fact = de facto
for this = ad hoc
under oath = affidavit
elsewhere = alibi
agreement = consensus
above, beyond = super
before midday = ante meridiem (a.m.)
after midday = post meridiem (p.m.)
after writing = post script (p.s.)
rest in peace = resquiescat in pace (R.I.P.)
please answer = répondez s'il vous plait (R.S.V.P.)
already seen = déjà vu
etc.

Languages are often borrowing words from each other for stylistic reasons. Heck, even the Japanese word for Masterpiece, "Kessaku," is originally Chinese. And the English word "Masterpiece" is Franco-Latin. If we wanted to use Pure English, then "Masterpiece" would be LORDBIT. And I suppose if you wanted to use Pure Japanese it would be 傑れたの作り物 (Suguretanotsukurimono).

TL;DR = the reason why Japanese use English words is for the same reason why English speakers use French and Latin words. Cos it looks/sounds cool.
Here's what "Transformers Masterpiece" would be called if we translated it from Franco-Latin to Pure English