Learn Russian: Компания всегда компенсирует расходы на отель. - The company always compensates hotel expenses.

The adverb всегда (always) is the key. It indicates a habitual, recurring action. Because of this context, we know компенсирует is functioning as an imperfective verb here.

If компенсирует is biaspectual, could this exact same word form be used for the future tense?

Yes! Present tense imperfective and future tense perfective share the same conjugation forms for biaspectual verbs. If you changed the context to a single completed action in the future (for example, by using завтра instead of всегда), компенсирует would act as a perfective verb meaning 'will compensate'.

Why do we say расходы на отель (Accusative) instead of using the Genitive case like расходы отеля?

To express what money is spent on, Russian uses расходы на plus the Accusative case. If you said расходы отеля (Genitive), it would mean 'the hotel's expenses' (the money the hotel itself spends), rather than the company's expenses to pay for the hotel.

Is there a difference between using отель and гостиница in this sentence?

They are highly synonymous and both work perfectly here. Отель feels slightly more modern, international, or business-oriented, which fits naturally with the corporate context of a компания reimbursing expenses.