Evite Invitations

I am in a wedding coming up in June. We are in the process of planning the engagement party. It will be very casual, from about 4-6pm on a Saturday, at a restaurant/bar. We will have a total of about 40 people (including spouses). Would it be improper to use Evite for this party? The bride even suggested it! We are planning to definitely use nice invitations for the bridal shower and of course they will have wedding invitations....please give me some opinions on this...the bridal party is having some controversy over this subject! Thank you!