One question does not need a form.
A Google Form usually arrives as a link. The recipient leaves the email, opens the form, and fills it in. That is the right shape for a long survey. For a yes, a no, an RSVP, a headcount, or a one-question poll, the question can live on the email.
What Google Forms is
Google Forms is a form you create and then share. The usual way to send it by email is a link. The recipient leaves the inbox, opens the form, and submits their answers. Responses are collected with the form. It is built for a survey that can run to many questions. Google also lets you include the form in the email for some people reading in Gmail. Other mail apps still get the link. In both cases the person is completing a form, and the response is stored with the form.
What Easy Reply is
Easy Reply adds one question and two to four answers to a Gmail you are already writing. The recipient does not install anything. They click once. That click records the answer, and you see it on the thread. It is for a quick yes or no, an RSVP, a headcount, or a one-question poll. A long survey still belongs in a form.
Side by side
What you send
Easy Reply. The email you are writing, with the question and the answers on it.
Google Forms. A link to a form you made separately.
What the recipient does
Easy Reply. Clicks one answer in the email. They do not install Easy Reply.
Google Forms. Opens the form from the link, fills it in, and submits. Some Gmail readers can answer a form included in the message.
What it is good for
Easy Reply. One quick question: yes or no, an RSVP, a headcount, or a one-question poll.
Google Forms. A longer survey, with as many questions as the form needs.
Where the answer goes
Easy Reply. The click is recorded, and you see it on the thread.
Google Forms. The response is stored with the form.
When to use Google Forms
Use Google Forms when you need a real survey: several questions, a record outside the thread, or answers someone will sort later. A guest list with notes from every person belongs in a form.
When to use Easy Reply
Use Easy Reply when the email is one question. Coming or not. Yes, no, or maybe. One seat or two. They click once in the email, the answer is recorded, and you see it.
FAQ
Is Easy Reply a Google Forms alternative for a yes or no?
For one question, yes. You put the answers on the email. They click once. You see the answer. Keep Google Forms when the survey has several questions, or when the record should live outside the thread.
Do they have to leave the email to answer a Google Form?
If you send the link, they leave the inbox, open the form, and submit it. Some Gmail readers can fill in a form that was included in the message. Either way they are completing a form, and the response is stored with the form. Easy Reply is a click on the email.
Can answer buttons collect an RSVP or a headcount?
Yes, when the choice fits in two to four short answers. Yes, no, or maybe. One seat, two, or more. If you also need a guest list or notes from every person, send a form for that part.
Free for 50 sends a month. The other person does not install anything.