Two different jobs that share one word
Both products turn speech into text, which is why they end up in the same search results, and that is roughly where the similarity stops.
Otter is a capture tool. Something is being said — a client call, a stand-up, an interview, a lecture — and you want a record of it. It records the audio, produces a transcript, works out who was speaking, and gives you a summary you can share. You read the output afterwards.
VoiceSnap Pro is an input method. Nothing is being recorded and nobody else is talking. You are the one composing, and the text is going straight into a field: the reply box, the ticket, the commit message, the document. You do not read the output afterwards, you send it.