Is it important to have integers inserted using %d rather than %s?

Going by the description for the $format argument

An array of formats to be mapped to each of the value in $data. If string, that format will be used for all of the values in $data. A format is one of ‘%d’, ‘%f’, ‘%s’ (integer, float, string). If omitted, all values in $data will be treated as strings unless otherwise specified in wpdb::$field_types.

So unless the type is important for your column structure you can leave it as string.

You can however create a dynamic format array if you want to, something like this.

$data = [
    'This is a string', // string
    55, // integer
    3.7, // float (double)
    true, // boolean
];

$format = array_map(function ($value) {
    switch (gettype($value)) {
        case 'string':
            return '%s';
        case 'integer':
            return '%d';
        case 'double':
            return '%f';
        default:
            return '%s';
    }
}, $data);

print_r($format);

You can test this on https://3v4l.org/

What we have here is a basic format builder based on the type of each array element, we always default to %s, also there is no need for a break; as we always return.

You can create a function out of this if you see that you use this multiple times, that was you can keep your code DRY.

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