Should the app name and tagline use the same font especially if the app name uses an irregular font (like Instagram's font). The tagline will be beneath the app name. I am just curious if this will cause a confusion to the user.
For cases where the user needs to read viable information.
Such as (and not limited to):
- Functions within the app.
- Tool bars
- Long bodies of text
- And any description
It is always good to use a legible "non-display" font.
In terms of branding, theoretically no, your tagline can follow the same style as your logo if you feel that is necessary.
But some questions you might need to ask are:
Does your tagline explain or give hints on what the app does?
For people who have never encountered the app before, will the tagline benefit them in explaining the use of the app?
Is your brand so immediately recognisable that people not reading / able to read the tagline will not be affected?
It might be worth considering to use a normal font to ensure all your potential users understand what is going on.
Examples. Here are some companies that use their own "display" font for a tagline, some are more legible than others.
Of course for some of them the tagline has no direct hint/information on what the brand does. e.g If you don't know what TESCO is "every little helps" won't really tell you much about the company.
And here are some taglines that opted for a legible font in the tagline. Either because it would just not be legible in the original "logo-font" or because the tagline actually gives you some good information/hints on what the app does.
It's all up to you and your product. If you still cannot decide, test! See what your own potential users think.
Instagram has a logo that was handmade for the brand, instagram is not using a font for its logo. So of course every text is using a font that looks different from their logo.
To answer your question: Most of the time using a different font for stuff like taglines is okay, but when for example the logo uses a font like Helvetica Bold for the name, then the tagline should be in different font-weight of that family so for example Helvetica Regular or Helvetica Light.
Contrast is important and helps the users to build mental separations.